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Sample records for steelhead trout oncorhynchus

  1. Growth of age-0 steelhead (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) in the Pine River watershed, Alcona County, Michigan

    SciTech Connect

    Bellgraph, Brian J.; Thompson, Bradley E.; Hayes, Daniel B.; Riley, Timothy S.

    2006-12-01

    We sampled ten sites within the Pine River watershed, Alcona County, Michigan. In 2001, age-0 steelhead (Oncorhynchus mykiss) were collected to determine growth rates. In 2002, emergence dates of steelhead were determined by observational studies and age-0 steelhead and brook trout (Salvelinus fontinalis) were collected to determine growth rates. Steelhead emergence occurred from late June to mid-July 2002. Growth rates of both species varied among branches within the watershed (P<0.05). Steelhead growth varied from 0.24 to 0.42 mm/day and brook trout growth varied from 0.22 to 0.37 mm/day.

  2. Stress of formalin treatment in juvenile spring chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Salmo gairdneri)

    USGS Publications Warehouse

    Wedemeyer, Gary; Yasutake, W.T.

    1973-01-01

    The physiological stress of 200 ppm formalin treatments at 10 C is more severe in the juvenile steelhead trout (Salmo gairdneri) than in the spring chinook salmon (Oncorhynchus tshawytscha). In the steelhead, a marked hypochloremia follows a 1-hr treatment and recovery requires about 24 hr. During longer treatments, hypercholesterolemia together with reduced regulatory precision, hypercortisolemia, alkaline reserve depletion, and hypocapnia unaccompanied by a fall in blood pH occur — suggestive of compensated respiratory alkalosis. In the spring chinook, hypochloremia and reduced plasma cholesterol regulatory precision are the significant treatment side effects but recovery requires only a few hours.Formalin treatments also cause epithelial separation, hypertrophy, and necrosis in the gills of both fishes but again, consistent with the physiological dysfunctions, these are more severe in the steelhead.

  3. Fluvial rainbow trout contribute to the colonization of steelhead (Oncorhynchus mykiss) in a small stream

    USGS Publications Warehouse

    Weigel, Dana E.; Connolly, Patrick J.; Powell, Madison S.

    2013-01-01

    Life history polymorphisms provide ecological and genetic diversity important to the long term persistence of species responding to stochastic environments. Oncorhynchus mykiss have complex and overlapping life history strategies that are also sympatric with hatchery populations. Passive integrated transponder (PIT) tags and parentage analysis were used to identify the life history, origin (hatchery or wild) and reproductive success of migratory rainbow/steelhead for two brood years after barriers were removed from a small stream. The fluvial rainbow trout provided a source of wild genotypes to the colonizing population boosting the number of successful spawners. Significantly more parr offspring were produced by anadromous parents than expected in brood year 2005, whereas significantly more parr offspring were produced by fluvial parents than expected in brood year 2006. Although hatchery steelhead were prevalent in the Methow Basin, they produced only 2 parr and no returning adults in Beaver Creek. On average, individual wild steelhead produced more parr offspring than the fluvial or hatchery groups. Yet, the offspring that returned as adult steelhead were from parents that produced few parr offspring, indicating that high production of parr offspring may not be related to greater returns of adult offspring. These data in combination with other studies of sympatric life histories of O. mykiss indicate that fluvial rainbow trout are important to the conservation and recovery of steelhead and should be included in the management and recovery efforts.

  4. Experimental hexamitiasis in juvenile coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdner)

    USGS Publications Warehouse

    1965-01-01

    An exogenous strain of cultured Hexamita salmonis (Moore) was employed to induce trophic hexamitiasis in otherwise disease-free juveniles of coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdneri). Mortality and growth were the parameters used to detect the effects of hexamitiasis on the two species. Two levels of each of the three experimental factors under study, Hexamita infection, species of fish, and density of fish, were arranged in a three-way factorial design. Replicate lots involved a total of 1,440 fish held under controlled laboratory conditions.Comparisons of growth and mortality indicate that infection with H. salmonis over a period of 8 weeks is innocuous to coho salmon. Steelhead trout suffered a low, but statistically significant mortality which subsided after the sixth week; growth rate was not affected.

  5. Genetic variation underlying resistance to infectious hematopoietic necrosis virus in a steelhead trout (Oncorhynchus mykiss) population

    USGS Publications Warehouse

    Brieuc, Marine S. O.; Purcell, Maureen K.; Palmer, Alexander D.; Naish, Kerry A.

    2015-01-01

    Understanding the mechanisms of host resistance to pathogens will allow insights into the response of wild populations to the emergence of new pathogens. Infectious hematopoietic necrosis virus (IHNV) is endemic to the Pacific Northwest and infectious to Pacific salmon and trout (Oncorhynchus spp.). Emergence of the M genogroup of IHNV in steelhead trout O. mykiss in the coastal streams of Washington State, between 2007 and 2011, was geographically heterogeneous. Differences in host resistance due to genetic change were hypothesized to be a factor influencing the IHNV emergence patterns. For example, juvenile steelhead trout losses at the Quinault National Fish Hatchery (QNFH) were much lower than those at a nearby facility that cultures a stock originally derived from the same source population. Using a classical quantitative genetic approach, we determined the potential for the QNFH steelhead trout population to respond to selection caused by the pathogen, by estimating the heritability for 2 traits indicative of IHNV resistance, mortality (h2 = 0.377 (0.226 - 0.550)) and days to death (h2 = 0.093 (0.018 - 0.203)). These results confirm that there is a genetic basis for resistance and that this population has the potential to adapt to IHNV. Additionally, genetic correlation between days to death and fish length suggests a correlated response in these traits to selection. Reduction of genetic variation, as well as the presence or absence of resistant alleles, could affect the ability of populations to adapt to the pathogen. Identification of the genetic basis for IHNV resistance could allow the assessment of the susceptibility of other steelhead populations.

  6. Some physiological aspects of sublethal heat stress in the juvenile steelhead trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch)

    USGS Publications Warehouse

    Wedemeyer, Gary

    1973-01-01

    A rapid (3 min) but sublethal temperature increase from 10 to 20 imposed a greater stress on juvenile coho salmon (Oncorhynchus kisutch) than on juvenile steelhead trout (Salmo gairdneri). Both species suffered hyperglycemia, hypocholesterolemia, increased blood hemoglobin, and decreased blood sugar regulatory precision, but the steelhead recovered more quickly. Acid–base equilibrium was essentially unaffected, and only the coho suffered any significant interrenal vitamin C depletion. Vitamin C normalization required about 24 hr.

  7. Over the falls? Rapid evolution of ecotypic differentiation in steelhead/rainbow trout (Oncorhynchus mykiss).

    PubMed

    Pearse, Devon E; Hayes, Sean A; Bond, Morgan H; Hanson, Chad V; Anderson, Eric C; Macfarlane, R Bruce; Garza, John Carlos

    2009-01-01

    Adaptation to novel habitats and phenotypic plasticity can be counteracting forces in evolution, but both are key characteristics of the life history of steelhead/rainbow trout (Oncorhynchus mykiss). Anadromous steelhead reproduce in freshwater river systems and small coastal streams but grow and mature in the ocean. Resident rainbow trout, either sympatric with steelhead or isolated above barrier dams or waterfalls, represent an alternative life-history form that lives entirely in freshwater. We analyzed population genetic data from 1486 anadromous and resident O. mykiss from a small stream in coastal California with multiple barrier waterfalls. Based on data from 18 highly variable microsatellite loci (He = 0.68), we conclude that the resident population above one barrier, Big Creek Falls, is the result of a recent anthropogenic introduction from the anadromous population of O. mykiss below the falls. Furthermore, fish from this above-barrier population occasionally descend over the falls and have established a genetically differentiated below-barrier subpopulation at the base of the falls, which appears to remain reproductively isolated from their now-sympatric anadromous ancestors. These results support a hypothesis of rapid evolution of a purely resident life history in the above-barrier population in response to strong selection against downstream movement. PMID:19561050

  8. Use of streambed substrate as refuge by steelhead or rainbow trout Oncorhynchus mykiss during simulated freshets.

    PubMed

    Ligon, F K; Nakamoto, R J; Harvey, B C; Baker, P F

    2016-04-01

    A flume was used to estimate the carrying capacity of streambed substrates for juvenile steelhead or rainbow trout Oncorhynchus mykiss seeking refuge from simulated freshets. The simulated freshets had mean water column velocities of c. 1·1 m s(-1) . The number of O. mykiss finding cover within the interstices of the substrate was documented for different substrate sizes and levels of embeddedness. The availability of suitable refuges determined the carrying capacity of the substrate for O. mykiss. For the size of the O. mykiss tested [mean ± s.d. fork length (LF ) = 122 ± 12·6 mm], the number of interstices with depths ≥200 mm measured with a 14·0 mm diameter flexible plastic tube was the best predictor of the number of O. mykiss able to find cover (r(2)  = 0·75). Oncorhynchus mykiss seeking refuge from freshets may need deeper interstices than those seeking concealment at autumn or winter base flows. The availability of interstices suitable as refuge from high flows may determine autumn and winter carrying capacity. PMID:26932205

  9. Genetic Architecture of Migration-Related Traits in Rainbow and Steelhead Trout, Oncorhynchus mykiss

    PubMed Central

    Hecht, Benjamin C.; Thrower, Frank P.; Hale, Matthew C.; Miller, Michael R.; Nichols, Krista M.

    2012-01-01

    Although migration plays a critical role in the evolution and diversification of species, relatively little is known of the genetic architecture underlying this life history in any species. Rainbow and steelhead trout (Oncorhynchus mykiss) naturally segregate for both resident and migratory life-history types, respectively, as do other members of the salmonid family of fishes. Using an experimental cross derived from wild resident rainbow and wild migratory steelhead trout from Southeast Alaska and high throughput restriction-site associated DNA (RAD) tag sequencing, we perform a quantitative trait locus (QTL) analysis to identify the number, position, and relative contribution of genetic effects on a suite of 27 physiological and morphological traits associated with the migratory life history in this species. In total, 37 QTL are localized to 19 unique QTL positions, explaining 4–13.63% of the variation for 19 of the 27 migration-related traits measured. Two chromosomal positions, one on chromosome Omy12 and the other on Omy14 each harbor 7 QTL for migration-related traits, suggesting that these regions could harbor master genetic controls for the migratory life-history tactic in this species. Another QTL region on Omy5 has been implicated in several studies of adaptive life histories within this species and could represent another important locus underlying the migratory life history. We also evaluate whether loci identified in this out-crossed QTL study colocalize to genomic positions previously identified for associations with migration-related traits in a doubled haploid mapping family. PMID:22973549

  10. Individual condition and stream temperature influence early maturation of rainbow and steelhead trout, Oncorhynchus mykiss

    USGS Publications Warehouse

    McMillan, J.R.; Dunham, J.B.; Reeves, G.H.; Mills, J.S.; Jordan, C.E.

    2012-01-01

    Alternative male phenotypes in salmonine fishes arise from individuals that mature as larger and older anadromous marine-migrants or as smaller and younger freshwater residents. To better understand the processes influencing the expression of these phenotypes we examined the influences of growth in length (fork length) and whole body lipid content in rainbow trout (Oncorhynchus mykiss). Fish were sampled from the John Day River basin in northeast Oregon where both anadromous ("steelhead") and freshwater resident rainbow trout coexist. Larger males with higher lipid levels had a greater probability of maturing as a resident at age-1+. Among males, 38% were maturing overall, and the odds ratios of the logistic model indicated that the probability of a male maturing early as a resident at age-1+ increased 49% (95% confidence interval (CI) = 23-81%) for every 5 mm increase in length and 33% (95% CI = 10-61%) for every 0. 5% increase in whole body lipid content. There was an inverse association between individual condition and water temperature as growth was greater in warmer streams while whole body lipid content was higher in cooler streams. Our results support predictions from life history theory and further suggest that relationships between individual condition, maturation, and environmental variables (e. g., water temperature) are shaped by complex developmental and evolutionary influences. ?? 2011 Springer Science+Business Media B.V.

  11. Individual condition and stream temperature influence early maturation of rainbow and steelhead trout, Oncorhynchus mykiss

    USGS Publications Warehouse

    McMillan, John R.; Dunham, J.B.; Reeves, G.H.; Mills, J.S.; Jordan, C.E.

    2012-01-01

    Alternative male phenotypes in salmonine fishes arise from individuals that mature as larger and older anadromous marine-migrants or as smaller and younger freshwater residents. To better understand the processes influencing the expression of these phenotypes we examined the influences of growth in length (fork length) and whole body lipid content in rainbow trout (Oncorhynchus mykiss). Fish were sampled from the John Day River basin in northeast Oregon where both anadromous ("steelhead") and freshwater resident rainbow trout coexist. Larger males with higher lipid levels had a greater probability of maturing as a resident at age-1+. Among males, 38% were maturing overall, and the odds ratios of the logistic model indicated that the probability of a male maturing early as a resident at age-1+ increased 49% (95% confidence interval (CI) = 23-81%) for every 5 mm increase in length and 33% (95% CI = 10-61%) for every 0.5% increase in whole body lipid content. There was an inverse association between individual condition and water temperature as growth was greater in warmer streams while whole body lipid content was higher in cooler streams. Our results support predictions from life history theory and further suggest that relationships between individual condition, maturation, and environmental variables (e.g., water temperature) are shaped by complex developmental and evolutionary influences.

  12. Investigations of Bull Trout (Salvelinus Confluentus), Steelhead Trout (Oncorhynchus Mykiss), and Spring Chinook Salmon (O. Tshawytscha) Interactions in Southeast Washington Streams. Final Report 1992.

    SciTech Connect

    Underwood, Keith D.

    1995-01-01

    The goal of this two year study was to determine if supplementation with hatchery reared steelhead trout (Oncorhynchus mykiss) and spring chinook salmon (O. tshawytscha) negatively impacted wild native bull trout (Salvelinus confluentus) through competitive interactions. Four streams with varying levels of fish supplementation activity were sampled in Southeast Washington. Tasks performed during this study were population density, relative abundance, microhabitat utilization, habitat availability, diet analysis, bull trout spawning ground surveys, radio telemetry of adult bull trout, and growth analysis. Results indicate that bull trout overlapped geographically with the supplemented species in each of the study streams suggesting competition among species was possible. Within a stream, bull trout and the supplemented species utilized dissimilar microhabitats and microhabitat utilization by each species was the same among streams suggesting that there was no shifts in microhabitat utilization among streams. The diet of bull trout and O. mykiss significantly overlapped in each of the study streams. The stream most intensely supplemented contained bull trout with the slowest growth and the non-supplemented stream contained bull trout with the fastest growth. Conversely, the stream most intensely supplemented contain steelhead with the fastest growth and the non-supplemented stream contained steelhead with the slowest growth. Growth indicated that bull trout may have been negatively impacted from supplementation, although other factors may have contributed. At current population levels, and current habitat quantity and quality, no impacts to bull trout as a result of supplementation with hatchery reared steelhead trout and spring chinook salmon were detected. Project limitations and future research recommendations are discussed.

  13. Using broad landscape level features to predict redd densities of steelhead trout (Oncorhynchus mykiss) and Chinook Salmon (Oncorhynchus tshawytscha) in the Methow River watershed, Washington

    USGS Publications Warehouse

    Romine, Jason G.; Perry, Russell W.; Connolly, Patrick J.

    2013-01-01

    We used broad-scale landscape feature variables to model redd densities of spring Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) in the Methow River watershed. Redd densities were estimated from redd counts conducted from 2005 to 2007 and 2009 for steelhead trout and 2005 to 2009 for spring Chinook salmon. These densities were modeled using generalized linear mixed models. Variables examined included primary and secondary geology type, habitat type, flow type, sinuosity, and slope of stream channel. In addition, we included spring effect and hatchery effect variables to account for high densities of redds near known springs and hatchery outflows. Variables were associated with National Hydrography Database reach designations for modeling redd densities within each reach. Reaches were assigned a dominant habitat type, geology, mean slope, and sinuosity. The best fit model for spring Chinook salmon included sinuosity, critical slope, habitat type, flow type, and hatchery effect. Flow type, slope, and habitat type variables accounted for most of the variation in the data. The best fit model for steelhead trout included year, habitat type, flow type, hatchery effect, and spring effect. The spring effect, flow type, and hatchery effect variables explained most of the variation in the data. Our models illustrate how broad-scale landscape features may be used to predict spawning habitat over large areas where fine-scale data may be lacking.

  14. Cold-acclimation leads to differential regulation of the steelhead trout (Oncorhynchus mykiss) coronary microcirculation

    PubMed Central

    Costa, Isabel A. S. F.; Hein, Travis W.

    2015-01-01

    The regulation of vascular resistance in fishes has largely been studied using isolated large conductance vessels, yet changes in tissue perfusion/vascular resistance are primarily mediated by the dilation/constriction of small arterioles. Thus we adapted mammalian isolated microvessel techniques for use in fish and examined how several agents affected the tone/resistance of isolated coronary arterioles (<150 μm ID) from steelhead trout (Oncorhynchus mykiss) acclimated to 1, 5, and 10°C. At 10°C, the vessels showed a concentration-dependent dilation to adenosine (ADE; 61 ± 8%), sodium nitroprusside (SNP; 35 ± 10%), and serotonin (SER; 27 ± 2%) (all values maximum responses). A biphasic response (mild contraction then dilation) was observed in vessels exposed to increasing concentrations of epinephrine (EPI; 34 ± 9% dilation) and norepinephrine (NE; 32 ± 7% dilation), whereas the effect was less pronounced with bradykinin (BK; 12.5 ± 3.5% constriction vs. 6 ± 6% dilation). Finally, a mild constriction was observed after exposure to acetylcholine (ACh; 6.5 ± 1.4%), while endothelin (ET)-1 caused a strong dose-dependent increase in tone (79 ± 5% constriction). Acclimation temperature had varying effects on the responsiveness of vessels. The dilations induced by EPI, ADE, SER, and SNP were reduced/eliminated at 5°C and/or 1°C as compared with 10°C. In contrast, acclimation to 5 and 1°C increased the maximum constriction induced by ACh and the sensitivity of vessels to ET-1 (but not the maximum response) at 1°C was greater. Acclimation temperature had no effect on the response to NE, and responsiveness to BK was variable. PMID:25715834

  15. Investigations of Bull Trout (Salvelinus Confluentus), Steelhead Trout (Oncorhynchus Mykiss), and Spring Chinook Salmon (O. Tshawytscha) Interactions in Southeast Washington Streams : 1991 Annual Report.

    SciTech Connect

    Martin, Steven W.

    1992-07-01

    Bull trout (Salvelinus confluentus) are native to many tributaries of the Snake River in southeast Washington. The Washington Department of Wildlife (WDW) and the American Fisheries Society (AFS) have identified bull trout as a species of special concern which means that they may become threatened or endangered by relatively, minor disturbances to their habitat. Steelhead trout/rainbow trout (Oncorhynchus mykiss) and spring chinook salmon (O.tshawytscha) are also native to several tributaries of the Snake river in southeast Washington. These species of migratory fishes are depressed, partially due to the construction of several dams on the lower Snake river. In response to decreased run size, large hatchery program were initiated to produce juvenile steelhead and salmon to supplement repressed tributary stocks, a practice known as supplementation. There is a concern that supplementing streams with artificially high numbers of steelhead and salmon may have an impact on resident bull trout in these streams. Historically, these three species of fish existed together in large numbers, however, the amount of high-quality habitat necessary for reproduction and rearing has been severely reduced in recent years, as compared to historic amounts. The findings of the first year of a two year study aimed at identifying species interactions in southeast Washington streams are presented in this report. Data was collected to assess population dynamics; habitat utilization and preference, feeding habits, fish movement and migration, age, condition, growth, and the spawning requirements of bull trout in each of four streams. A comparison of the indices was then made between the study streams to determine if bull trout differ in the presence of the putative competitor species. Bull trout populations were highest in the Tucannon River (supplemented stream), followed by Mill Creek (unsupplemented stream). Young of the year bull trout utilized riffle and cascade habitat the most in all

  16. Testing of male sockeye salmon (Oncorhynchus nerka) and steelhead trout (Salmo gairdneri) for infectious hematopoietic necrosis virus

    USGS Publications Warehouse

    Mulcahy, D.; Pascho, R.J.; Batts, W.N.

    1987-01-01

    Infectious hematopoietic necrosis (IHN) virus has been isolated only rarely from whole milt samples of male sockeye salmon (Oncorhynchus nerka). In 3 yr of testing, virus incidences in males ranged from 0 to 13% when milt was sampled but were 60–100% with spleen or kidney. When IHN virus was isolated from sockeye salmon milt at titers less than 3.00 log10 plaque-forming units (pfu)/mL, the level of virus in the kidney or spleen exceeded 7.00 log10 pfu/g. Higher rates of IHN virus isolation from kidney or spleen than from milt were also generally found in steelhead trout (Salmo gairdneri), although the differences were less pronounced than in sockeye salmon. Furthermore, virus was sometimes isolated from steelhead trout milt when the level of virus in kidney or spleen samples was very low, and was recovered from some milt samples when none was isolated from the corresponding spleen sample. When male salmonids are tested for IHN virus, kidney or spleen samples are superior to whole milt, but milt should be included for critical examinations.

  17. Novel molecular markers differentiate Oncorhynchus mykiss (rainbow trout and steelhead) and the O. clarki (cutthroat trout) subspecies

    USGS Publications Warehouse

    Ostberg, C.O.; Rodriguez, R.J.

    2002-01-01

    A suite of 26 PCR-based markers was developed that differentiates rainbow (Oncorhynchus mykiss) and coastal cutthroat trout (O. clarki clarki). The markers also differentiated rainbow from other cutthroat trout subspecies (O. clarki), and several of the markers differentiated between cutthroat trout subspecies. This system has numerous positive attributes, including: nonlethal sampling, high species-specificity and products that are easily identified and scored using agarose gel electrophoresis. The methodology described for developing the markers can be applied to virtually any system in which numerous markers are desired for identifying or differentiating species or subspecies.

  18. Some physiological consequences of handling stress in the juvenile coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdneri)

    USGS Publications Warehouse

    Wedemeyer, Gary

    1972-01-01

    The stress of handling juvenile coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdneri) in soft water and in water with added salts was evaluated using blood and tissue chemistry fluctuations as indices of metabolic and endocrine function. Changes in plasma glucose, chloride, calcium, and cholesterol levels indicated that significant osmoregulatory and metabolic dysfunctions can occur and persist for about 24 hr after handling in soft water. Pituitary activation, as judged by lack of interrenal ascorbate depletion, did not occur. Increasing the ambient NaCl and Ca++ levels to about 100 milliosmols and 75–120 ppm, respectively, partially or completely alleviated the hyperglycemia and hypochloremia indicating that the stress of handling had been reduced.

  19. The effect of diet on dorsal fin erosion in steelhead trout (Oncorhynchus mykiss)

    USGS Publications Warehouse

    Lellis, W.A.; Barrows, F.T.

    1997-01-01

    A 2 X 2 factorial experiment of diet type (krill vs. fish meal) and steroid supplementation (0 vs. 30 ??g 17??-methyltestosterone kg-1) was conducted to determine the effects on dorsal fin erosion in steelhead trout. Triplicate tanks of 250 fry were fed one of the four diets at a rate calculated to produce 115 g fish in 34 weeks. Fish were transferred to larger tanks when mean density index reached 0.40. Dorsal fin index (DFI, measured as mean dorsal fin height X 100/total fish length) was greater (P < 0.001) among fish fed krill-based diets than for fish fed fish-based diets at weeks 12, 22, and 34 of the trial. Added testosterone decreased (p = 0.04) DFI among fish fed the krill diet at week 12 but otherwise had no effect on fin condition. Addition of testosterone to either diet type decreased (P = 0.02) critical thermal maximum, which is a measure of fish resistance to thermal stress. The results suggest that diet composition can influence the rate of dorsal fin erosion in steelhead trout through a metabolic, behavioral, or combined change.

  20. Shifting Thresholds: Rapid Evolution of Migratory Life Histories in Steelhead/Rainbow Trout, Oncorhynchus mykiss.

    PubMed

    Phillis, Corey C; Moore, Jonathan W; Buoro, Mathieu; Hayes, Sean A; Garza, John Carlos; Pearse, Devon E

    2016-01-01

    Expression of phenotypic plasticity depends on reaction norms adapted to historic selective regimes; anthropogenic changes in these selection regimes necessitate contemporary evolution or declines in productivity and possibly extinction. Adaptation of conditional strategies following a change in the selection regime requires evolution of either the environmentally influenced cue (e.g., size-at-age) or the state (e.g., size threshold) at which an individual switches between alternative tactics. Using a population of steelhead (Oncorhynchus mykiss) introduced above a barrier waterfall in 1910, we evaluate how the conditional strategy to migrate evolves in response to selection against migration. We created 9 families and 917 offspring from 14 parents collected from the above- and below-barrier populations. After 1 year of common garden-rearing above-barrier offspring were 11% smaller and 32% lighter than below-barrier offspring. Using a novel analytical approach, we estimate that the mean size at which above-barrier fish switch between the resident and migrant tactic is 43% larger than below-barrier fish. As a result, above-barrier fish were 26% less likely to express the migratory tactic. Our results demonstrate how rapid and opposing changes in size-at-age and threshold size contribute to the contemporary evolution of a conditional strategy and indicate that migratory barriers may elicit rapid evolution toward the resident life history on timescales relevant for conservation and management of conditionally migratory species. PMID:26585381

  1. Performance of juvenile steelhead trout (Oncorhynchus mykiss) produced from untreated and cryopreserved milt

    USGS Publications Warehouse

    Hayes, Michael C.; Rubin, Stephen P.; Hensleigh, Jay E.; Reisenbichler, Reginald R.; Wetzel, Lisa A.

    2005-01-01

    Despite the expanding use of milt cryopreservation in aquaculture, the performance of fish produced from this technique has not been fully explored beyond initial rearing stages. We compared the performance of juvenile steelhead Oncorhynchus mykiss produced from untreated (UM) and cryopreserved milt (CM) and reared for 4–9 months. For the 1996 brood, CM alevins were heavier (∼ 1.7%, P < 0.01) than UM alevins and length was influenced by a significant milt-by-family interaction (P < 0.03) suggesting a greater treatment effect for some families. No significant differences were found in length or weight (P > 0.05) for 1997 brood alevins and percent yolk was similar for both broods (P > 0.34). In growth and survival experiment I (GSE-I, 1996), UM and CM juveniles reared in separate tanks and fed to satiation (130 days) showed no significant differences in survival, length or weight (P > 0.05) between milt groups. In contrast, for UM and CM siblings reared in the same tank for 210 days on a low food ration (GSE-II), survival was similar (P > 0.05), but length (UM 4% > CM, P < 0.05) and possibly weight (UM 15% > CM, P = 0.08), were influenced by cryopreservation. Fish from the 1997 brood (GSE-III) were reared for 313 days in a repeat of GSE-II and no differences were found in survival (P = 0.47), length (P = 0.75) or weight (P = 0.76) suggesting considerable heterogeneity between broods. Performance of the 1996 brood was also tested for response to stress and a disease challenge. Cortisol responses of juveniles exposed to acute stress were not significantly different (P = 0.19), but mean cortisol was consistently and significantly greater (P < 0.01) for CM than UM fish exposed to a 48-h stress (increased density). After exposure to three dosages of the bacteria, Listonella anguillarum, we found similar mortality proportions (P = 0.72) for UM and CM fish. Variable juvenile performance for the parameters tested indicated significant

  2. The role of beaver in shaping steelhead trout (Oncorhynchus mykiss) habitat complexity and thermal refugia in a central Oregon stream

    NASA Astrophysics Data System (ADS)

    Consolati, F.; Wheaton, J. M.; Neilson, B. T.; Bouwes, N.; Pollock, M. M.

    2012-12-01

    The incised and degraded habitat of Bridge Creek, tributary to the John Day River in central Oregon, is thought to be limiting the local population of ESA-listed steelhead trout (Oncorhynchus mykiss). Restoration efforts for this watershed are aimed to improve their habitat through reconnecting the channel with portions of its former floodplain (now terraces) to increase stream habitat complexity and the extent of riparian vegetation. This is being done via the installation of over a hundred beaver dam support (BDS) structures that are designed to either mimic beaver dams or support existing beaver dams. The overall objective of this study is to determine if the BDS structures have had an effect on stream channel habitat complexity and thermal refugia in selected sections of Bridge Creek. Analysis of stream temperature data in restoration treatment and control areas will show the effects of beaver dams on stream temperature. Analysis of aerial imagery and high resolution topographic data will exhibit how the number and types of geomorphic units have changed after the construction of beaver dams. Combined, the results of this research are aimed to increase our understanding of how beaver dams impact fish habitat and stream temperature.

  3. Spatial partitioning and asymmetric hybridization among sympatric coastal steelhead trout (Oncorhynchus mykiss irideus), coastal cutthroat trout (O. clarki clarki) and interspecific hybrids

    USGS Publications Warehouse

    Ostberg, C.O.; Slatton, S.L.; Rodriguez, R.J.

    2004-01-01

    Hybridization between sympatric species provides unique opportunities to examine the contrast between mechanisms that promote hybridization and maintain species integrity. We surveyed hybridization between sympatric coastal steelhead (Oncorhynchus mykiss irideus) and coastal cutthroat trout (O. clarki clarki) from two streams in Washington State, Olsen Creek (256 individuals sampled) and Jansen Creek (431 individuals sampled), over a 3-year period. We applied 11 O. mykiss-specific nuclear markers, 11 O. c. clarki-specific nuclear markers and a mitochondrial DNA marker to assess spatial partitioning among species and hybrids and determine the directionality of hybridization. F1 and post-F1 hybrids, respectively, composed an average of 1.2% and 33.6% of the population sampled in Jansen Creek, and 5.9% and 30.4% of the population sampled in Olsen Creek. A modest level of habitat partitioning among species and hybrids was detected. Mitochondrial DNA analysis indicated that all F 1 hybrids (15 from Olsen Creek and five from Jansen Creek) arose from matings between steelhead females and cutthroat males implicating a sneak spawning behaviour by cutthroat males. First-generation cutthroat backcrosses contained O. c. clarki mtDNA more often than expected suggesting natural selection against F1 hybrids. More hybrids were backcrossed toward cutthroat than steelhead and our results indicate recurrent hybridization within these creeks. Age analysis demonstrated that hybrids were between 1 and 4 years old. These results suggest that within sympatric salmonid hybrid zones, exogenous processes (environmentally dependent factors) help to maintain the distinction between parental types through reduced fitness of hybrids within parental environments while divergent natural selection promotes parental types through distinct adaptive advantages of parental phenotypes.

  4. The impact of small irrigation diversion dams on the recent migration rates of steelhead and redband trout (Oncorhynchus mykiss)

    USGS Publications Warehouse

    Weigel, Dana E.; Connolly, Patrick J.; Powell, Madison S.

    2013-01-01

    Barriers to migration are numerous in stream environments and can occur from anthropogenic activities (such as dams and culverts) or natural processes (such as log jams or dams constructed by beaver (Castor canadensis)). Identification of barriers can be difficult when obstructions are temporary or incomplete providing passage periodically. We examine the effect of several small irrigation diversion dams on the recent migration rates of steelhead (Oncorhynchus mykiss) in three tributaries to the Methow River, Washington. The three basins had different recent migration patterns: Beaver Creek did not have any recent migration between sites, Libby Creek had two-way migration between sites and Gold Creek had downstream migration between sites. Sites with migration were significantly different from sites without migration in distance, number of obstructions, obstruction height to depth ratio and maximum stream gradient. When comparing the sites without migration in Beaver Creek to the sites with migration in Libby and Gold creeks, the number of obstructions was the only significant variable. Multinomial logistic regression identified obstruction height to depth ratio and maximum stream gradient as the best fitting model to predict the level of migration among sites. Small irrigation diversion dams were limiting population interactions in Beaver Creek and collectively blocking steelhead migration into the stream. Variables related to stream resistance (gradient, obstruction number and obstruction height to depth ratio) were better predictors of recent migration rates than distance, and can provide important insight into migration and population demographic processes in lotic species.

  5. Fatty-acid profiles of white muscle and liver in stream-maturing steelhead trout Oncorhynchus mykiss from early migration to kelt emigration.

    PubMed

    Penney, Z L; Moffitt, C M

    2015-01-01

    The profiles of specific fatty acids (FA) in white muscle and liver of fasting steelhead trout Oncorhynchus mykiss were evaluated at three periods during their prespawning migration and at kelt emigration in the Snake-Columbia River of Washington, Oregon and Idaho, to improve the understanding of energy change. Twenty-seven FAs were identified; depletion of 10 of these was positively correlated in liver and white muscle of prespawning O. mykiss. To observe relative changes in FA content more accurately over sampling intervals, the lipid fraction of tissues was used to normalize the quantity of individual FA to an equivalent tissue wet mass. Saturated and monounsaturated FAs were depleted between upstream migration in September and kelt emigration in June, whereas polyunsaturated FAs were more conserved. Liver was depleted of FAs more rapidly than muscle. Three FAs were detected across all sampling intervals: 16:0, 18:1 and 22:6n3, which are probably structurally important to membranes. When structurally important FAs of O. mykiss are depleted to provide energy, physiological performance and survival may be affected. PMID:25424636

  6. Fatty-acid profiles of white muscle and liver in stream-maturing steelhead trout Oncorhynchus mykiss from early migration to kelt emigration

    USGS Publications Warehouse

    Penney, Zachary L.; Moffitt, Christine M.

    2015-01-01

    The profiles of specific fatty acids (FA) in white muscle and liver of fasting steelhead troutOncorhynchus mykiss were evaluated at three periods during their prespawning migration and at kelt emigration in the Snake–Columbia River of Washington, Oregon and Idaho, to improve the understanding of energy change. Twenty-seven FAs were identified; depletion of 10 of these was positively correlated in liver and white muscle of prespawning O. mykiss. To observe relative changes in FA content more accurately over sampling intervals, the lipid fraction of tissues was used to normalize the quantity of individual FA to an equivalent tissue wet mass. Saturated and monounsaturated FAs were depleted between upstream migration in September and kelt emigration in June, whereas polyunsaturated FAs were more conserved. Liver was depleted of FAs more rapidly than muscle. Three FAs were detected across all sampling intervals: 16:0, 18:1 and 22:6n3, which are probably structurally important to membranes. When structurally important FAs of O. mykiss are depleted to provide energy, physiological performance and survival may be affected.

  7. Upstream movement of residual hatchery steelhead into areas containing bull trout and cutthroat trout.

    SciTech Connect

    McMichael, Geoffrey A. ); Pearsons, Todd N.

    2000-11-01

    Hatchery-reared steelhead Oncorhynchus mykiss that do not emigrate as smolts shortly after release may negatively impact wild fish communities through ecological interactions. We used systematic, stratified snorkeling surveys to document the relative abundance of wild rainbow trout O. mykiss, bull trout Salvelinus confluentus, and westslope cutthroat trout O. clarki lewisi as well as the upstream limit of residual hatchery steelhead (hatchery-reared steelhead that had failed to emigrate before June 1). Our objective was to determine whether residual hatchery steelhead had migrated upstream from their release point into an area containing a threatened population of bull trout and cutthroat trout. Hatchery steelhead made up a larger portion of the salmonid community in the sites near their release location (mean= 52.5%, range= 29-79%), and constituted a lower proportion (mean= 4.8%, range= 0-14%) of the salmonid community as distance upstream of the release location increased. However, residual hatchery steelhead had migrated over 12 km upstream into an area containing a threatened stock of bull trout and westslope cutthroat trout O. clarki lewisi.

  8. Steelhead trout Oncorhynchus mykiss metabolic rate is affected by dietary Aloe vera inclusion but not by mounting an immune response against formalin-killed Aeromonas salmonicida.

    PubMed

    Zanuzzo, F S; Urbinati, E C; Nash, G W; Gamperl, A K

    2015-07-01

    The oxygen consumption (MO2) of two groups of 10° C acclimated steelhead trout Oncorhynchus mykiss was measured for 72 h after they were given a 100 µl kg(-1) intraperitoneal injection of formalin-killed Aeromonas salmonicida (ASAL) or phosphate-buffered saline (PBS). In addition, plasma cortisol levels were measured in fish from both groups prior to, and 1 and 3 h after, they were given a 30 s net stress. The first group was fed an unaltered commercial diet for 4 weeks, whereas the second group was fed the same diet but with 0·5% (5 g kg(-1) ) Aloe vera powder added; A. vera has potential as an immunostimulant for use in aquaculture, but its effects on basal and acute phase response (APR)-related metabolic expenditures and stress physiology, are unknown. Injection of ASAL v. PBS had no measurable effect on the MO2 of O. mykiss indicating that the APR in this species is not associated with any net increase in energy expenditure. In contrast, incorporating 0·5% A. vera powder into the feed decreased routine metabolic rate by c. 8% in both injection groups and standard metabolic rate in the ASAL-injected group (by c. 4 mg O2 kg(-1) h(-1) ; 5%). Aloe vera fed fish had resting cortisol levels that were approximately half of those in fish on the commercial diet (c. 2·5 v. 5·0 ng ml(-1) ), but neither this difference nor those post-stress reached statistical significance (P > 0·05). PMID:26010230

  9. Spring Outmigration of Wild and Hatchery Chinook Salmon and Steelhead Trout Smolts from the Imnaha River; 1994 Annual Report.

    SciTech Connect

    Ashe, Becky L.; Miller, Alan C.; Kucera, Paul A.

    1995-01-01

    In 1994, the Nez Perce Tribe began a smolt monitoring study on the Imnaha River in cooperation with the Fish Passage Center (FPC). A rotary screw trap was used to collect emigrating wild and hatchery chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) smolts from March 1 to June 15, 1994. We PIT tagged and released 956 wild chinook salmon, 661 hatchery chinook salmon, 1,432 wild steelhead trout and 2,029 hatchery steelhead trout. Cumulative interrogation rates at mainstem Snake and Columbia River dams were 62.2% for wild chinook salmon, 45.2% for hatchery chinook salmon, 51.3% for wild steelhead trout, and 34.3% for hatchery steelhead trout.

  10. Spring Outmigration of Wild and Hatchery Chinook Salmon and Steelhead Trout Smolts from the Imnaha River, Oregon; 1996 Annual Report.

    SciTech Connect

    Blenden, Michael L.; Rocklage, Stephen J.; Kucera, Paul A.

    1997-04-01

    For the third consecutive year, the Nez Perce Tribe, in conjunction with the Fish Passage Center, participated in the smolt monitoring program in the Imnaha River. A rotary screw trap was used to collect emigrating wild and hatchery chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) smolts from February 23 to June 24, 1996. A total of 1,797 wild chinook salmon, 11,896 hatchery chinook salmon, 3,786 wild steelhead trout, and 31,094 hatchery steelhead trout smolts were captured during outmigration studies on the Imnaha River in 1996. Mortality associated with trapping, handling and tagging was low, being 1.4% for wild chinook, 0.18% for hatchery chinook, 0.21% for wild steelhead and 0.28% for hatchery steelhead trout smolts.

  11. Early ocean survival and marine movements of hatchery and wild steelhead trout ( Oncorhynchus mykiss) determined by an acoustic array: Queen Charlotte Strait, British Columbia

    NASA Astrophysics Data System (ADS)

    Welch, David W.; Ward, Bruce R.; Batten, Sonia D.

    2004-03-01

    Early ocean movements, residency, and survival of steelhead (Oncorhynchus mykiss) were examined in Queen Charlotte Strait, a large (20×100 km2) marine area separating Vancouver Island from the mainland. The results provide the first detailed data on the ocean biology of hatchery and wild steelhead smolts. Initial ocean movements were not strongly directed, with most smolts swimming in the range of 0.2-0.5 body length (BL) s-1. The majority (78%) vacated Queen Charlotte Strait within 1 week of release in freshwater. Relative marine survival of hatchery smolts surgically implanted 1 month prior to release was identical to that of wild smolts implanted on the day of release; survival of hatchery smolts transported to the study site, implanted, and released all on the same day was significantly lower. The results suggest that the early marine survival of hatchery and wild smolts may be fundamentally similar, but that the cumulative stress of transportation and surgery may reduce post-surgery survival. Hatchery smolts moved at higher average swimming speeds than wild smolts, but the difference was not statistically significant. Early marine survival within the study region appears to be relatively high (⩾55%), contradicting assumptions that the early marine phase is the critical period for determining salmon recruitment.

  12. Characterization of 22 novel single nucleotide polymorphism markers in steelhead and rainbow trout

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty-two individuals representing coastal and inland populations of steelhead and rainbow trout (Oncorhynchus mykiss) were sequenced at 15 ESTs and 9 microsatellite loci to identify single nucleotide polymorphisms (SNPs). Sixty-two polymorphisms were discovered during the screen and 13 were devel...

  13. Compendium of Low-Cost Pacific Salmon and Steelhead Trout Production Facilities and Practices in the Pacific Northwest.

    SciTech Connect

    Senn, Harry G.

    1984-09-01

    The purpose was to research low capital cost salmon and steelhead trout production facilities and identify those that conform with management goals for the Columbia Basin. The species considered were chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), sockeye salmon (O. nerka), and steelhead trout (Salmo gairdneri). This report provides a comprehensive listing of the facilities, techniques, and equipment used in artificial production in the Pacific Northwest. (ACR)

  14. Spatial segregation of spawning habitat limits hybridization between sympatric native Steelhead and Coastal Cutthroat Trout

    USGS Publications Warehouse

    Buehrens, T.W.; Glasgow, J.; Ostberg, Carl O.; Quinn, T.P.

    2013-01-01

    Native Coastal Cutthroat Trout Oncorhynchus clarkii clarkii and Coastal Steelhead O. mykiss irideus hybridize naturally in watersheds of the Pacific Northwest yet maintain species integrity. Partial reproductive isolation due to differences in spawning habitat may limit hybridization between these species, but this process is poorly understood. We used a riverscape approach to determine the spatial distribution of spawning habitats used by native Coastal Cutthroat Trout and Steelhead as evidenced by the distribution of recently emerged fry. Molecular genetic markers were used to classify individuals as pure species or hybrids, and individuals were assigned to age-classes based on length. Fish and physical habitat data were collected in a spatially continuous framework to assess the relationship between habitat and watershed features and the spatial distribution of parental species and hybrids. Sampling occurred in 35 reaches from tidewaters to headwaters in a small (20 km2) coastal watershed in Washington State. Cutthroat, Steelhead, and hybrid trout accounted for 35%, 42%, and 23% of the fish collected, respectively. Strong segregation of spawning areas between Coastal Cutthroat Trout and Steelhead was evidenced by the distribution of age-0 trout. Cutthroat Trout were located farther upstream and in smaller tributaries than Steelhead were. The best predictor of species occurrence at a site was the drainage area of the watershed that contributed to the site. This area was positively correlated with the occurrence of age-0 Steelhead and negatively with the presence of Cutthroat Trout, whereas hybrids were found in areas occupied by both parental species. A similar pattern was observed in older juveniles of both species but overlap was greater, suggesting substantial dispersal of trout after emergence. Our results offer support for spatial reproductive segregation as a factor limiting hybridization between Steelhead and Coastal Cutthroat Trout.

  15. Emergence of MD type infectious hematopoietic necrosis virus in Washington State coastal steelhead trout

    USGS Publications Warehouse

    Breyta, Rachel; Jones, Amelia; Stewart, Bruce; Brunson, Ray; Thomas, Joan; Kerwin, John; Bertolini, Jim; Mumford, Sonia; Patterson, Chris; Kurath, Gael

    2013-01-01

    Infectious hematopoietic necrosis virus (IHNV) occurs in North America as 3 major phylogenetic groups designated U, M, and L. In coastal Washington State, IHNV has historically consisted of U genogroup viruses found predominantly in sockeye salmon Oncorhynchus nerka. M genogroup IHNV, which has host-specific virulence for rainbow and steelhead trout O. mykiss, was detected only once in coastal Washington prior to 2007, in an epidemic among juvenile steelhead trout in 1997. Beginning in 2007 and continuing through 2011, there were 8 IHNV epidemics in juvenile steelhead trout, involving 7 different fish culture facilities in 4 separate watersheds. During the same time period, IHNV was also detected in asymptomatic adult steelhead trout from 6 coastal watersheds. Genetic typing of 283 recent virus isolates from coastal Washington revealed that the great majority were in the M genogroup of IHNV and that there were 2 distinct waves of viral emergence between the years 2007 and 2011. IHNV type mG110M was dominant in coastal steelhead trout during 2007 to 2009, and type mG139M was dominant between 2010 and 2011. Phylogenetic analysis of viral isolates indicated that all coastal M genogroup viruses detected in 1997 and 2007 to 2011 were part of the MD subgroup and that several novel genetic variants related to the dominant types arose in the coastal sites. Comparison of spatial and temporal incidence of coastal MD viruses with that of the rest of the Pacific Northwest indicated that the likely source of the emergent viruses was Columbia River Basin steelhead trout

  16. Emergence of MD type infectious hematopoietic necrosis virus in Washington State coastal steelhead trout.

    PubMed

    Breyta, Rachel; Jones, Amelia; Stewart, Bruce; Brunson, Ray; Thomas, Joan; Kerwin, John; Bertolini, Jim; Mumford, Sonia; Patterson, Chris; Kurath, Gael

    2013-06-13

    Infectious hematopoietic necrosis virus (IHNV) occurs in North America as 3 major phylogenetic groups designated U, M, and L. In coastal Washington State, IHNV has historically consisted of U genogroup viruses found predominantly in sockeye salmon Oncorhynchus nerka. M genogroup IHNV, which has host-specific virulence for rainbow and steelhead trout O. mykiss, was detected only once in coastal Washington prior to 2007, in an epidemic among juvenile steelhead trout in 1997. Beginning in 2007 and continuing through 2011, there were 8 IHNV epidemics in juvenile steelhead trout, involving 7 different fish culture facilities in 4 separate watersheds. During the same time period, IHNV was also detected in asymptomatic adult steelhead trout from 6 coastal watersheds. Genetic typing of 283 recent virus isolates from coastal Washington revealed that the great majority were in the M genogroup of IHNV and that there were 2 distinct waves of viral emergence between the years 2007 and 2011. IHNV type mG110M was dominant in coastal steelhead trout during 2007 to 2009, and type mG139M was dominant between 2010 and 2011. Phylogenetic analysis of viral isolates indicated that all coastal M genogroup viruses detected in 1997 and 2007 to 2011 were part of the MD subgroup and that several novel genetic variants related to the dominant types arose in the coastal sites. Comparison of spatial and temporal incidence of coastal MD viruses with that of the rest of the Pacific Northwest indicated that the likely source of the emergent viruses was Columbia River Basin steelhead trout. PMID:23759556

  17. Histological assessment of organs in sexually mature and post-spawning steelhead trout and insights into iteroparity

    USGS Publications Warehouse

    Penney, Zachary L.; Moffitt, Christine M.

    2014-01-01

    Steelhead trout (Oncorhynchus mykiss) are anadromous and iteroparous, but repeat-spawning rates are generally low. Like other anadromous salmonids, steelhead trout fast during freshwater spawning migrations, but little is known about the changes that occur in vital organs and tissues. We hypothesized that fish capable of repeat-spawning would not undergo the same irreversible degeneration and cellular necrosis documented in semelparous salmon. Using Snake River steelhead trout as a model we used histological analysis to assess the cellular architecture in the pyloric stomach, ovary, liver, and spleen in sexually mature and kelt steelhead trout. We observed 38 % of emigrating kelts with food or fecal material in the gastrointestinal tract. Evidence of feeding was more likely in good condition kelts, and feeding was associated with a significant renewal of villi in the pyloric stomach. No vitellogenic oocytes were observed in sections of kelt ovaries, but perinucleolar and early/late stage cortical alveolus oocytes were present suggesting iteroparity was possible. We documented a negative correlation between the quantity of perinucleolar oocytes in ovarian tissues and fork length of kelts suggesting that larger steelhead trout may invest more into a single spawning event. Liver and spleen tissues of both mature and kelt steelhead trout had minimal cellular necroses. Our findings indicate that the physiological processes causing rapid senescence and death in semelparous salmon are not evident in steelhead trout, and recovery begins in fresh water. Future management efforts to increase iteroparity in steelhead trout and Atlantic salmon must consider the physiological processes that influence post-spawning recovery.

  18. Smolt Monitoring Program, Volume I, Migrational Characteristics of Columbia Basin Salmon and Steelhead Trout, 1986 Annual Report.

    SciTech Connect

    Fish Passage Center

    1987-02-01

    This report presents the results of post-seasonal analyses including timing and relative magnitude of the outmigration, travel time for marked hatchery releases, and survival in mid-Columbia and lower Snake River index reaches. Travel time of marked yearling and sub-yearling chinook salmon (Oncorhynchus tsawytscha), sockeye salmon (Oncorhynchus nerka), and steelhead trout (Salmo gairdneri) is measured between specific sampling points in the system. Marked groups usually represent major hatchery production stocks. Survival estimates are computed for specific spring chinook and steelhead marked groups. Arrival time and duration of outmigration of the chinook, sockeye, coho (Oncorhynchus kisutch) and steelhead runs are reported at key sampling points. Hatchery and brand release information for 1986 is also listed.

  19. Environmental enrichment in steelhead (Oncorhynchus mykiss) hatcheries: Field evaluation of aggression, foraging, and territoriality in natural and hatchery fry

    USGS Publications Warehouse

    Tatara, C.P.; Riley, S.C.; Scheurer, J.A.

    2008-01-01

    Reforms for salmonid hatcheries include production of hatchery fish with behavioral characteristics similar to wild conspecifics. Enrichment of the hatchery environment has been proposed to achieve this goal. Field experiments of steelhead (i.e., sea-run rainbow trout, Oncorhynchus mykiss) fry from a common stock reared under natural (i.e., stream), enriched hatchery, and conventional hatchery conditions indicated no significant differences in the rates of foraging or aggression between rearing treatments. However, the rates of foraging and aggression of natural fry were significantly affected by the type of hatchery fry stocked with them. Natural steelhead fry fed at lower rates and exhibited higher rates of aggression when stocked with steelhead fry raised in enriched hatchery environments. Territory sizes of steelhead fry ranged from 0.015 to 0.801 m2; were significantly, positively related to body length; and were not significantly different between rearing treatments. We conclude that hatchery steelhead fry released into streams establish territories that are proportional to their body length and similar in size to territories of natural steelhead fry. Our results indicate that both conventional and enriched hatchery environments produce natural social behaviors in steelhead released as fry and that fry from enriched hatchery environments may alter the foraging and aggressive behavior of natural, resident steelhead fry. ?? 2008 NRC.

  20. Spring Outmigration of Wild and Hatchery Chinook Salmonid Steelhead Trout Smolts from the Imnaha River, Oregon; 1995 Annual Report.

    SciTech Connect

    Blenden, Michael L.; Kucera, Paul A.; Osborne, Randall S.

    1996-04-01

    For the second consecutive year, the Nez Perce Tribe, in conjunction with the Fish Passage Center, participated in the smolt monitoring program in the Imnaha River. A rotary screw trap was used to collect emigrating wild and hatchery chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) smolts from February 6 to June 20, 1995. We PIT tagged and released 421 wild chinook salmon smolts, 747 hatchery chinook salmon smolts (445 HxW and 302 HxH), 227 wild steelhead trout smolts and 1,296 hatchery steelhead trout smolts. Cumulative interrogation rates at mainstem Snake and Columbia River dams were 78.4% for wild chinook salmon, 58.9% for hatchery chinook salmon (HxW), 56.6% for hatchery chinook salmon (HxH), 76.2% for wild steelhead trout, and 69.2% for hatchery steelhead trout. Peak outmigration of NPT tagged wild Imnaha River chinook salmon smolts occurred from early to mid-May at Lower Granite, Little Goose, and Lower Monumental Dams. Median and 90% passage dates for wild chinook salmon smolts at Lower Granite Dam were May 1 and May 11, respectively. Continuous spill at Lower Granite Dam was initiated on May 3 and lasted for 51 days. The 90% passage date of wild chinook salmon smolts at Lower Granite Dam (May 11) preceded peak Snake River and Lower Granite (June 6) flows by 26 days. Although hatchery chinook salmon exhibited a shorter outmigration period through the Snake River than their wild counterparts, peak arrival for both groups occurred at approximately the same time. Median and 90% passage dates at Lower Granite Dam for other PIT tagged groups were: hatchery chinook salmon (NPT-HxW) - May 2 and May 13; hatchery chinook salmon (FPC-HxH) - May 8 and May 15; wild steelhead trout - May 2 and May 9; and hatchery steelhead trout (NPT and FPC) - May 31 and June 16. Hatchery steelhead trout displayed small peaks in arrival timing at Lower Granite and Little Goose Dams in mid-May to mid-June.

  1. Sediment Dynamics and Southern Steelhead Habitat (Oncorhynchus mykiss) in the Matilija Creek Watershed, Southern California

    NASA Astrophysics Data System (ADS)

    Minear, J. T.; Kondolf, G. M.

    2003-12-01

    Matilija Creek, one of two principal forks of the Ventura River, drains 142 km2 in the Transverse Ranges of southern California. Thanks to rapid tectonic uplift and weak clastic rocks, sediment yields exceed 1200 m3/km2 annually. Matilija Dam was built in 1947 with an initial capacity of 8 million m3 and is now nearly full of sediment. The dam is structurally unsafe, blocks anadromous fish migration, and is being considered for removal. The Ventura River has one of the southernmost runs of steelhead trout (Oncorhynchus mykiss), with an average of approximately 2,500 annually migrating up Matilija Creek before the dam was built. The high sediment yields and highly variable flow regime have raised questions about the interactions among high flows, sediment transfer from lower order tributaries to the third order channels used by the fish, and fish life history. Previous studies in Southern California have documented sediment yields (especially following debris flows and fires, and mostly in the San Gabriel Mountains), but the interaction of geomorphic processes and aquatic habitat in this highly episodic environment is not well understood. We used a combination of mapping and survey techniques, sediment traps, grain size analysis, lithologic analysis and scour rods to study intra-annual geomorphic processes and sediment dynamics affecting Southern Steelhead habitat in the Matilija Creek area in 16 study pools over the 2002 and 2003 flow seasons (dry and "normal", respectively) and found little sediment was deposited or scoured from pools. However, other processes not previously recognized significantly affected the steelhead habitat in the study pools including tufa cementation (carbonate deposition) and alder root growth in spawning gravels, as well as seasonal desiccation of some reaches. Removal of Matilija Dam will reopen suitable habitat to steelhead trout, but managers should recognize that habitat quality is likely to vary considerably from year

  2. Migrational Characteristics of Columbia Basin Salmon and Steelhead Trout, Part II, Smolt Monitoring Program, 1984 Annual Report.

    SciTech Connect

    McConnaha, Willis E.

    1985-07-01

    The report describes the travel time of marked yearling and sub-yearling chinook salmon (Oncorhynchus tshawytscha), sockeye salmon (O. nerka), and steelhead trout (Salmo gairdneri) between points within the system, and reports the arrival timing and duration of the migrations for these species as well as coho salmon (O. kisutch). A final listing of 1984 hatchery releases is also included. 8 refs., 26 figs., 20 tabs.

  3. Identification of steelhead and resident rainbow trout progeny in the Deschutes River, Oregon, revealed with otolith microchemistry

    USGS Publications Warehouse

    Zimmerman, C.E.; Reeves, G.H.

    2002-01-01

    Comparisons of strontium:calcium (Sr:Ca) ratios in otolith primordia and freshwater growth regions were used to identify the progeny of steelhead Oncorhynchus mykiss (anadromous rainbow trout) and resident rainbow trout in the Deschutes River, Oregon. We cultured progeny of known adult steelhead and resident rainbow trout to confirm the relationship between Sr:Ca ratios in otolith primordia and the life history of the maternal parent. The mean (??SD) Sr:Ca ratio was significantly higher in the otolith primordia of the progeny of steelhead (0.001461 ?? 0.00029; n = 100) than in those of the progeny of resident rainbow trout (0.000829 ?? 0.000012; n = 100). We used comparisons of Sr:Ca ratios in the primordia and first-summer growth regions of otoliths to determine the maternal origin of unknown O. mykiss juveniles (n = 272) collected from rearing habitats within the main-stem Deschutes River and tributary rearing habitats and thus to ascertain the relative proportion of each life history morph in each rearing habitat. Resident rainbow trout fry dominated the bi-monthly samples collected from main-stem rearing habitats between May and November 1995. Steelhead fry dominated samples collected from below waterfalls on two tributaries in 1996 and 1998.

  4. Successful mitigation of viral disease based on a delayed exposure rearing strategy at a large-scale steelhead trout conservation hatchery

    USGS Publications Warehouse

    Breyta, R.; Samson, Corie; Blair, Marilyn; Black, Allison; Kurath, Gael

    2015-01-01

    In 2009, the largest steelhead trout conservation hatchery in the state of Idaho, Dworshak National Fish Hatchery (NFH), lost over 50% of the juvenile steelhead trout (Oncorhynchus mykiss) population being reared for release. The causative agent of this high mortality was the viral pathogen infectious hematopoietic necrosis virus (IHNV). This was neither the first nor the worst epidemic of IHNV to occur at the hatchery, but it was the worst in over a decade. Genetic analysis of IHNV isolates taken from juveniles suffering epidemic IHN disease in 2009 revealed that the virus was of the M group of IHNV viruses, known to have high virulence for trout. The water supply for steelhead trout rearing at Dworshak NFH is untreated water taken directly from the Clearwater River. Further genetic analysis of IHNV isolates from adults spawned in 2009 indicated that adult steelhead trout in the river (in the hatchery water supply) were the most probable transmission source for the epidemic IHN disease in the juvenile fish. Previously, Dworshak NFH had been able to gain access to reservoir water from behind the Dworshak Dam for nursery egg incubation and the earliest stage of fry rearing, which nearly eliminated incidence of IHN disease in that stage of rearing. Additionally, the nearby Clearwater State Fish Hatchery (SFH), which operates entirely with reservoir water, has never had a case of IHN disease in juvenile steelhead trout. Therefore, staff at Dworshak NFH sought and obtained access to a limited supply of reservoir water for the first few months of outdoor rearing of juvenile steelhead trout, beginning in 2010. This strategy delayed the exposure of juvenile steelhead trout to river water for several months. The effects of this program change were: drastic reduction in IHN disease in juvenile steelhead trout; interruption in the transmission of highly virulent M group IHNV from adult steelhead trout; no interruption in the transmission of low virulent U group IHNV from

  5. A comparison of susceptibility to Myxobolus cerebralis among strains of rainbow trout and steelhead in field and laboratory trials

    USGS Publications Warehouse

    Densmore, Christine L.; Blazer, V.S.; Cartwright, Deborah D.; Schill, W.B.; Schachte, J.H.; Petrie, C.J.; Batur, M.V.; Waldrop, T.B.; Mack, A.; Pooler, P.S.

    2001-01-01

    Three strains of rainbow trout and steelhead Oncorhynchus mykiss were evaluated for the presence of whirling disease in field and laboratory trials. In the field exposures, fingerling Salmon River steelhead and Cayuga Lake and Randolph strains of rainbow trout were placed in wire cages in an earthen, stream-fed pond in New York State that was known to harbor Myxobolus cerebralis. Control fish were held at another hatchery that was free of whirling disease. In the controlled trials at the National Fish Health Research Laboratory, fingerling steelhead and Cayuga Lake and Mount Lassen rainbow trout were exposed to triactinomyxons at low (200 triactinomyxons/fish) or high (2,000 triactinomyxons/fish) levels for 2 h. Controls of each group were sham-exposed. Following an incubation period of 154 d for laboratory trials and 180 d for field trials, cranial tissue samples were taken for spore enumeration (field and laboratory trials) and histological analyses (laboratory only). Clinical signs of disease, including whirling behavior, blacktail, and skeletal deformities, were recorded for each fish in the laboratory trial at the terminal sampling. No clinical evidence of disease was noted among fish in the field trials. Clinical signs were noted among all strains in the laboratory trials at both exposure levels, and these signs were consistently greatest for the Mount Lassen strain. Whirling and skeletal deformities were more evident in the steelhead than in the Cayuga Lake rainbow trout; blacktail was more common in the Cayuga Lake fish. In both field and laboratory trials, spore counts were significantly higher for Cayuga Lake rainbow trout than in steelhead. In laboratory trials, moderate to marked cranial tissue lesions predominated in all three strains.

  6. Rearing in a distorted magnetic field disrupts the ‘map sense’ of juvenile steelhead trout

    PubMed Central

    Putman, Nathan F.; Meinke, Amanda M.; Noakes, David L. G.

    2014-01-01

    We used simulated magnetic displacements to test orientation preferences of juvenile steelhead trout (Oncorhynchus mykiss) exposed to magnetic fields existing at the northernmost and southernmost boundaries of their oceanic range. Fish reared in natural magnetic conditions distinguished between these two fields by orienting in opposite directions, with headings that would lead fish towards marine foraging grounds. However, fish reared in a spatially distorted magnetic field failed to distinguish between the experimental fields and were randomly oriented. The non-uniform field in which fish were reared is probably typical of fields that many hatchery fish encounter due to magnetic distortions associated with the infrastructure of aquaculture. Given that the reduced navigational abilities we observed could negatively influence marine survival, homing ability and hatchery efficiency, we recommend further study on the implications of rearing salmonids in unnatural magnetic fields. PMID:24899681

  7. Intensive Evaluation and Monitoring of Chinook Salmon and Steelhead Trout Production, Crooked River and Upper Salmon River Sites, 1992 Annual Report.

    SciTech Connect

    Kiefer, Russell B.; Lockhart, Jerald N.

    1994-12-01

    The purpose of this intensive monitoring project is to determine the number of returning chinook salmon Oncorhynchus tshawytscha and steelhead trout 0. mykiss adults necessary to achieve optimal smolt production, and develop mitigation accounting based on increases in smolt production. Two locations in Idaho are being intensively studied to meet these objectives. Information from this research will be applied to parr monitoring streams statewide to develop escapement objectives and determine success of habitat enhancement projects.

  8. Smolt Monitoring Program, Volume II, Migrational Characteristics of Columbia Basin Salmon and Steelhead Trout, 1986 Annual Report.

    SciTech Connect

    Fish Passage Center

    1987-02-01

    Smolt Monitoring Program Annual Report, 1986, Volume I, describes the results of travel time monitoring and other migrational characteristics of yearling and sub-yearling chinook salmon (Oncorhynchus tshawytscha), sockeye salmon (Oncorhynchus nerka), and steelhead trout (Salmo gairdneri). This volume presents the data from Fish Passage Center freeze brands used in the analysis of travel time for Lewiston, Lower Granite, Lower Monumental, Rock Island, McNary, and John Day dams. Summary of data collection procedures and explanation of data listings are presented in conjunction with the mark recapture data. Data for marked fish not presented in this report will be provided upon request. Daily catch statistics (by species), flow, and sample parameters for the smolt monitoring sites, Clearwater, Lewiston, Lower Granite, Lower Monumental, Rock Island, McNary, John Day, and Bonneville also will be provided upon request.

  9. Ecological interactions between hatchery summer steelhead and wild Oncorhynchus mykiss in the Willamette River basin, 2014

    SciTech Connect

    Harnish, Ryan A.; Green, Ethan D.; Vernon, Christopher R.; Mcmichael, Geoffrey A.

    2014-12-23

    The purpose of this study was to determine the extent to which juvenile hatchery summer steelhead and wild winter steelhead overlap in space and time, to evaluate the extent of residualism among hatchery summer steelhead in the South Santiam River, and to evaluate the potential for negative ecological interactions among hatchery summer steelhead and wild winter steelhead. Because it is not possible to visually discern juvenile winter steelhead from resident rainbow trout, we treated all adipose-intact juvenile O. mykiss as one group that represented juvenile wild winter steelhead. The 2014 study objectives were to 1) estimate the proportion of hatchery summer steelhead that residualized in the South Santiam River in 2014, 2) determine the extent to which hatchery and naturally produced O. mykiss overlapped in space and time in the South Santiam River, and 3) characterize the behavioral interactions between hatchery-origin juvenile summer steelhead and naturally produced O. mykiss. We used a combination of radio telemetry and direct observations (i.e., snorkeling) to determine the potential for negative interactions between hatchery summer and wild winter steelhead juveniles in the South Santiam River. Data collected from these two independent methods indicated that a significant portion of the hatchery summer steelhead released as smolts did not rapidly emigrate from the South Santiam River in 2014. Of the 164 radio-tagged steelhead that volitionally left the hatchery, only 66 (40.2%) were detected outside of the South Santiam River. Forty-four (26.8% of 164) of the radio-tagged hatchery summer steelhead successfully emigrated to Willamette Falls. Thus, the last known location of the majority of the tagged fish (98 of 164 = 59.8%) was in the South Santiam River. Thirty-three of the tagged hatchery steelhead were detected in the South Santiam River during mobile-tracking surveys. Of those, 21 were found to be alive in the South Santiam River over three months after

  10. Kelt Reconditioning: A Research Project to Enhance Iteroparity in Columbia Basin Steelhead (Oncorhynchus mykiss), 2005-2006 Annual Report.

    SciTech Connect

    Branstetter, Ryan; Whiteaker, John; Hatch, Douglas R.

    2006-12-01

    Iteroparity, the ability to repeat spawn, is a natural life history strategy that is expressed by some species from the family Salmonidae. Estimated rates of repeat spawning for post-development Columbia River steelhead Oncorhynchus mykiss populations range from 1.6 to 17%. It is expected that currently observed iteroparity rates for wild steelhead in the Basin are severely depressed due to development and operation of the hydropower system and various additional anthropogenic factors. Increasing the current expression of repeat spawning rates using fish culturing methods could be a viable technique to assist the recovery of depressed steelhead populations, and could help reestablish this naturally occurring life history trait. Reconditioning is the process of culturing post-spawned fish (kelts) in a captive environment until they are able to reinitiate feeding, growth, and redevelop mature gonads. Reconditioning techniques were initially developed for Atlantic salmon Salmo salar and sea-trout S. trutta. The recent Endangered Species Act listing of many Columbia River Basin steelhead populations has prompted interest in developing reconditioning methods for wild steelhead populations within the Basin. To test kelt steelhead reconditioning as a potential recovery tool, wild emigrating steelhead kelts were placed into one of four study groups (in river release, direct capture and transport, short-term reconditioning, or long-term reconditioning). Steelhead kelts from the Yakima River were collected at the Chandler Juvenile Monitoring Facility (CJMF, located on the Yakima River at river kilometer 75.6) from 7 March to 8 June 2006. In total, 348 kelts were collected for reconditioning at Prosser Hatchery. Captive specimens represented 17.0% (348 of 2,002) of the entire 2005-2006 Yakima River wild steelhead population, based on fish ladder counts at Prosser Dam. Steelhead kelts were reconditioned in 20-foot circular tanks, and fed freeze-dried krill initially (first 2

  11. Kelt Reconditioning: A Research Project to Enhance Iteroparity in Columbia Basin Steelhead (Oncorhynchus mykiss), 2005 Annual Report.

    SciTech Connect

    Branstetter, Ryan; Whiteaker, John; Hatch, Douglas R.

    2006-01-01

    Iteroparity, the ability to repeat spawn, is a natural life history strategy that is expressed by some species from the family Salmonidae. Estimated rates of repeat spawning for post-development Columbia River steelhead Oncorhynchus mykiss populations range from 1.6 to 17%. It is expected that currently observed iteroparity rates for wild steelhead in the Basin are severely depressed due to development and operation of the hydropower system and various additional anthropogenic factors. Increasing the current expression of repeat spawning rates using fish culturing methods could be a viable technique to assist the recovery of depressed steelhead populations, and could help reestablish this naturally occurring life history trait. Reconditioning is the process of culturing post-spawned fish (kelts) in a captive environment until they are able to reinitiate feeding, growth, and redevelop mature gonads. Reconditioning techniques were initially developed for Atlantic salmon Salmo salar and sea-trout S. trutta. The recent Endangered Species Act listing of many Columbia River Basin steelhead populations has prompted interest in developing reconditioning methods for wild steelhead populations within the Basin. To test kelt steelhead reconditioning as a potential recovery tool, wild emigrating steelhead kelts were placed into one of four study groups (in river release, direct capture and transport, short-term reconditioning, or long-term reconditioning). Steelhead kelts from the Yakima River were collected at the Chandler Juvenile Monitoring Facility (CJMF, located on the Yakima River at river kilometer 75.6) from 11 March to 23 June 2005. In total, 519 kelts were collected for reconditioning at Prosser Hatchery. Captive specimens represented 15.0% (519 of 3,451) of the entire 2004-2005 Yakima River wild steelhead population, based on fish ladder counts at Prosser Dam. Steelhead kelts were reconditioned in 20-foot circular tanks, and fed freeze-dried krill initially (first 2

  12. Kelt Reconditioning: A Research Project to Enhance Iteroparity in Columbia Basin Steelhead (Oncorhynchus mykiss), 2003 Annual Report.

    SciTech Connect

    Hatch, Douglas R.; Branstetter, Ryan; Blodgett, Joe

    2004-03-01

    Repeat spawning is a life history strategy that is expressed by some species from the family Salmonidae. Rates of repeat spawning for post-development Columbia River steelhead Oncorhynchus mykiss populations range from 1.6 to 17%. It is expected that currently observed iteroparity rates for wild steelhead in the Basin are severely depressed due to development and operation of the hydropower system and various additional anthropogenic factors. Increasing the natural expression of historical repeat spawning rates using fish culturing methods could be a viable technique to assist the recovery of depressed steelhead populations. Reconditioning is the process of culturing post-spawned fish (kelts) in a captive environment until they are able to reinitiate feeding, growth, and redevelop mature gonads. Kelt reconditioning techniques were initially developed for Atlantic salmon Salmo salar and sea-trout S. trutta. The recent Endangered Species Act listing of many Columbia Basin steelhead populations has prompted interest in developing reconditioning methods for wild steelhead populations within the Basin. To test kelt steelhead reconditioning as a potential recovery tool, we captured wild emigrating steelhead kelts from the Yakima River and evaluated reconditioning (short and long-term) success and diet formulations at Prosser Hatchery on the Yakima River. Steelhead kelts from the Yakima River were collected at the Chandler Juvenile Monitoring Facility (CJMF, located on the Yakima River at river kilometer 75.6) from 12 March to 28 May 2003. In total, 690 kelts were collected for reconditioning at Prosser Hatchery. Captive specimens represented 30.8% (690 of 2,235) of the entire 2002-2003 Yakima River wild steelhead population, based on fish ladder counts at Prosser Dam. All steelhead kelts were reconditioned in circular tanks, fed freeze-dried krill and received hw-wiegandt multi vit dietary supplement; long-term steelhead kelts also received Moore-Clark pellets

  13. Clinostomum marginatum in steelhead trout (Salmo gairdneri) and cutthroat trout (Salmo clarki) in a western Washington lake

    USGS Publications Warehouse

    Uzmann, J.R.; Douglas, J.

    1966-01-01

    Clinostomum marginatum (Trematoda: Clinostomatidae), the yellow grub parasite, was recorded in epizootic proportions from Lynch Lake, King County, Washington, in 1961 and 1962. The parasite larvae occurred principally in steelhead trout (Salmo gairdneri); cutthroat trout (S. clarki) were infected to a relatively minor degree. Fish and snail host populations were destroyed by rotenone and copper sulfate treatments.

  14. Spring Emigration of Natural and Hatchery Chinook Salmon and Steelhead Trout Smolts from the Imnaha River, Oregon; 1997 Annual Report.

    SciTech Connect

    Blenden, Michael L.; Veach, Eric R.; Kucera, Paul A.

    1998-10-01

    For the fourth consecutive year, the Nez Perce Tribe, in conjunction with the Fish Passage Center, participated in the smolt monitoring program in the Imnaha River. A screw trap was used to collect emigrating natural and hatchery chinook salmon (Uncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) smolts from February 25 to June 27, 1997. A total of 270 natural chinook salmon, 10,616 hatchery chinook salmon, 864 natural steelhead trout (and 13 natural steelhead parr), and 7,345 hatchery steelhead trout smolts were captured during emigration studies on the Imnaha River. Mortality associated with trapping, handling and tagging was low: 0.37% for natural chinook, 0.11% for hatchery chinook, 0.11% for natural steelhead, and 0.39% for hatchery steelhead trout smolts. Natural chinook salmon smolts emigrated from the Imnaha River from February 25 to June 10 and had a mean length of 108 mm, average weight of 13 g, and mean condition factor of 1.02. The peak period of natural chinook smolt emigration, based on number of fish collected, occurred between March 25 and April 30. Hatchery reared chinook salmon smolts were collected from April 9 to May 9, with 99% of the smolts being caught within 10 days after release. Hatchery chinook smolts mean length, weight, and condition factor were 131 mm, 25.4 g, and 1.12, respectively. Emigration of natural steelhead smolts in the Imnaha River occurred between March 14 and June 25. Peak emigration occurred from May 1 to May 15. Natural steelhead smolts averaged 175 mm in fork length, 55.8 g in weight and had a mean condition factor of 1 .OO. Hatchery steelhead smolts emigrated from the Imnaha River between April 15 and June 27. Hatchery steelhead smolts averaged 210 mm in fork length, 88 g in weight and had a mean condition factor of 0.93. Spring runoff water conditions in 1997 provided above average flows for emigrating anadromous salmonid smolts. Imnaha River mean daily discharge during spring emigration ranged from 7

  15. Evaluation and Monitoring of Wild /Natural Steelhead Trout Production, 1996 Annual Report.

    SciTech Connect

    Leth, Brian D.; Holubetz, Terry B.; Nemeth, Doug

    2000-01-01

    This project was initiated to provide additional, and more definitive, information regarding wild steelhead Oncorhynchus mykiss populations in Idaho. Important streams for wild steelhead production were identified and selected for monitoring. Monitoring activities employed among streams varied, but generally included: aerial redd counts, placement of adult weirs, enumeration of juveniles through mask and snorkel counts, and emigrant trapping. This report details activities during the 1996 field season.

  16. Kelt Reconditioning: A Research Project to Enhance Iteroparity in Columbia Basin Steelhead (Oncorhynchus mykiss), 2001 Annual Report.

    SciTech Connect

    Hatch, Douglas R.; Anders, Paul J., Evans, Allen F.

    2002-12-01

    Repeat spawning is a life history strategy that is expressed by some species from the family Salmonidae. Rates of repeat spawning for post-development Columbia River steelhead (Oncorhynchus mykiss) populations range from 1.6 to 17%. It is expected that currently observed iteroparity rates for wild steelhead in the Basin are artificially and in some cases severely depressed due to development and operation of the hydropower system and various additional anthropogenic factors. Increasing the natural expression of historical repeat spawning rates using fish culturing means could be a viable technique to assist the recovery of depressed steelhead populations. Reconditioning is the process of culturing post-spawned fish (kelts) in a captive environment until they are able to reinitiate feeding, growth, and again develop mature gonads. Kelt reconditioning techniques were initially developed for Atlantic salmon (Salmo salar) and sea-trout (S. trutta). The recent Endangered Species Act listing of many Columbia Basin steelhead populations has prompted interest in developing reconditioning methods for wild steelhead populations within the Basin. To address recovery, we captured wild emigrating steelhead kelts from the Yakima River and tested reconditioning and the effects of several diet formulations on its success at Prosser Hatchery on the Yakama Reservation. Steelhead kelts from the Yakima River were collected at the Chandler Juvenile Evaluation Facility (CJEF, located at Yakima River kilometer 48) from 12 March to 5 July 2001. Kelts were reconditioned in circular tanks and fed a mixed diet of starter paste, adult sized trout pellets, and freeze-dried krill. Formalin was used to control outbreaks of fungus and we tested the use of Ivermectin{trademark}to control internal parasites (e.g., Salmincola spp.). Surviving specimens were released for natural spawning in two groups on 15 November 2001 and 18 January 2002. Overall success of the reconditioning process was based on

  17. Cryopreservation of sperm of the endangered gila trout, Oncorhynchus gilae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gila trout, Oncorhynchus gilae, are native to the headwaters of the Gila River drainage in New Mexico and Arizona and the headwaters of the Verde River drainage in Arizona. The species is currently protected as endangered under the Endangered Species Act. Cryopreservation of sperm is now a widely us...

  18. Toxicokinetics of perfluorooctane sulfonate in rainbow trout (Oncorhynchus mykiss)

    EPA Science Inventory

    Rainbow trout (Oncorhynchus mykiss) confined to respirometer-metabolism chambers were dosed with perfluorooctane sulfonate (PFOS) by intra-arterial injection and sampled to obtain concentration time-course data for plasma, and either urine or expired water. The data were then an...

  19. Kelt Reconditioning: A Research Project to Enhance Iteroparity in Columbia Basin Steelhead (Oncorhynchus mykiss), 2002 Annual Report.

    SciTech Connect

    Hatch, Douglas R.; Branstetter, Ryan; Blodgett, Joe

    2003-07-01

    Repeat spawning is a life history strategy that is expressed by some species from the family Salmonidae. Rates of repeat spawning for post-development Columbia River steelhead Oncorhynchus mykiss populations range from 1.6 to 17%. It is expected that currently observed iteroparity rates for wild steelhead in the Basin are severely depressed due to development and operation of the hydropower system and various additional anthropogenic factors. Increasing the natural expression of historical repeat spawning rates using fish culturing means could be a viable technique to assist the recovery of depressed steelhead populations. Reconditioning is the process of culturing post-spawned fish (kelts) in a captive environment until they are able to reinitiate feeding, growth, and again develop mature gonads. Kelt reconditioning techniques were initially developed for Atlantic salmon Salmo salar and sea-trout S. trutta. The recent Endangered Species Act listing of many Columbia Basin steelhead populations has prompted interest in developing reconditioning methods for wild steelhead populations within the Basin. To test kelt steelhead reconditioning as a potential recovery tool, we captured wild emigrating steelhead kelts from the Yakima River and evaluated reconditioning (short and long-term) success and diet formulations at Prosser Hatchery on the Yakima River. Steelhead kelts from the Yakima River were collected at the Chandler Juvenile Evaluation Facility (CJEF, located at Yakima River kilometer 48) from March 12 to June 13, 2002. In total, 899 kelts were collected for reconditioning at Prosser Hatchery. Captive specimens represented 19.8% (899 of 4,525) of the entire 2001-2002 Yakima River wild steelhead population, based on fish ladder counts at Prosser Dam. Kelts were reconditioned in circular tanks and were fed freeze-dried krill, Moore-Clark pellets, altered Moore-Clark pellets (soaked in krill extract and dyed), or a combination of the altered Moore

  20. Stock Identification of Columbia River Chinook Salmon and Steelhead Trout, 1986 Final Report.

    SciTech Connect

    Schreck, Carl B.; Li, Hiran W.; Hjort, Randy C.

    1986-08-01

    For the first time genetic similarities among chinook salmon and among steelhead trout stocks of the Columbia River were determined using a holistic approach including analysis of life history, biochemical, body shape and meristic characters. We examined between year differences for each of the stock characteristics and we also correlated the habitat characteristics with the wild stock characteristics. The most important principle for managing stocks of Columbia River chinook salmon and steelhead trout is that geographically proximal stocks tend to be like each other. Run timing and similarity of the stream systems should be taken into account when managing stocks. There are similarities in the classifications derived for chinook salmon and steelhead trout. Steelhead trout or chinook salmon tend to be genetically similar to other steelhead or chinook stocks, respectively, that originate from natal streams that are geographically close, regardless of time of freshwater entry. The primary exception Lo this trend is between stocks of spring and fall chinook in the upper Columbia River where fish with the different run timings are dissimilar, though geographically proximate stocks within a run form are generally very similar. Spring chinook stocks have stronger affinities to other spring chinook stocks that originate in the same side of the Cascade Range than to these Spring chinook stock: spawned on the other side of the Cascade Range. Spring chinook from west of the Cascades are more closely related to fall chinook than they are to spring chinook from east of the Cascades. Summer chinook can be divided into two main groups: (1) populations in the upper Columbia River that smolt as subyearlings and fall chinook stocks; and (2) summer chinook stocks from the Salmon River, Idaho, which smolt as yearlings and are similar to spring chinook stocks from Idaho. Fall chinook appear to comprise one large diverse group that is not easily subdivided into smaller subgroups. In

  1. Kelt Reconditioning: A Research Project to Enhance Iteroparity in Columbia Basin Steelhead (Oncorhynchus mykiss), 2000 Annual Report.

    SciTech Connect

    Evans, Allen F.; Beaty, Roy E.; Hatch, Douglas R.

    2001-12-01

    Repeat spawning is a life history strategy that is expressed by some species from the family salmonidae. Natural rates of repeat spawning for Columbia River steelhead Oncorhynchus mykiss populations range from 1.6 to 17%. Increasing this repeat spawning rate using fish culture techniques could assist the recovery of depressed steelhead populations. Reconditioning is the process of culturing post-spawned fish (kelts) in a captive environment until they are able to grow and develop mature gonads. Kelt reconditioning techniques were initially developed for Atlantic salmon Salmo salar and sea-trout S. trutta. The recent Endangered Species Act listing of many Columbia Basin steelhead populations has prompted interest in developing reconditioning methods for local populations. The primary purpose of this project in 2000 was to test the general feasibility of collecting, feeding, and treating steelhead kelts in a captive environment. Steelhead kelts were collected from the Yakima River at the Chandler Juvenile Evaluation Facility (Rkm 48) from 12 March to 13 June 2000. Kelts were reconditioned at adjacent Prosser Hatchery in both rectangular and circular tanks and fed a mixed diet of starter paste, adult sized trout pellets, and freeze-dried krill. Formalin was used to control outbreaks of fungus, and we tested the use of ivermectin to control internal parasites (e.g., Salmincola spp.). Some the kelts that died during the reconditioning process were analyzed via pathology and gonad histology to ascertain the possible cause of death and to describe their reproductive development at the time of death. All surviving specimens were released for natural spawning on 12 December 2000. Overall success of the reconditioning process was based on the proportion of fish that survived captivity, gained weight, and on the number of fish that successfully underwent gonadal recrudescence. Many of the reconditioned kelts were radio tagged to assess their spawning migration behavior and

  2. Stock Identification of Columbia River Chinook Salmon and Steelhead Trout, 1984-1985 Annual Report.

    SciTech Connect

    Schreck, Carl B.; Sharpe, Cameron; Li, Hiram W.

    1985-09-21

    Fish were collected from 60 stocks of chinook salmon and 62 stocks of steelhead trout. Electrophoretic analyses were completed on 43 stocks of chinook salmon and 41 stocks of steelhead trout and meristic counts were completed on 43 stocks of chinook and 41 stocks of steelhead. Statistical comparisons between year classes of our electrophoretic data indicate that most enzyme systems are stable over time but some may be dynamic and should be used with caution in our analyses. We also compared neighboring stocks of both spring chinook and steelhead trout. These comparisons were between stocks of the same race from adjacent stream systems and/or hatcheries. Differences in isozyme gene frequencies can be used to estimate genetic segregation between pairs of stocks. Analysis of the chinook data suggests that, as expected, the number of statistically significant differences in isozyme gene frequencies increases as the geographic distance between stocks increases. The results from comparisons between adjacent steelhead stocks were inconclusive and must await final analysis with more data. Cluster analyses using either isozyme gene frequencies or meristic characters both tended to group the chinook and steelhead stocks by geographic areas and by race and both methods resulted in generally similar grouping patterns. However, cluster analyses using isozyme gene frequencies produced more clusters than the analyses using meristic characters probably because of the greater number of electrophoretic characters compared to the number of meristic characters. Heterozygosity values for each stock were computed using the isozyme gene frequencies. The highest heterozygosity values for chinook were observed in summer chinook and the hatchery stocks while the lowest values were observed in the spring chinook and wild stocks. The results of comparisons of heterozygosity values among areas were inconclusive. The steelhead heterozygosity values were higher in the winter stocks than in the

  3. TOXICITY OF TRIVALENT CHROMIUM TO EARLY LIFE STAGES OF STEELHEAD TROUT

    EPA Science Inventory

    Acute and early life stage toxicity tests were conducted with trivalent chromium and steelhead trout (Salmo gairdneri). A 96-h LC50 of 4,400 micrograms/l chromium was obtained with two-month-old juvenile fish. Early life stage exposure from newly fertilized eggs to 30-d post-swim...

  4. EFFECT OF PENTACHLOROPHENOL ON THE GROWTH AND MORTALITY OF EMBRYONIC AND JUVENILE STEELHEAD TROUT

    EPA Science Inventory

    The toxicity of sodium pentachlorophenate to early life stages of steelhead trout (Salmo gairdneri) was investigated, using a flow-through exposure system. A 96-hr LC50 of 66 micrograms/l was derived for previously unexposed ten-week-old fry. A 72-day test, beginning 24 hr after ...

  5. EFFECTS OF SODIUM PENTACHLOROPHENATE ON SURVIVAL AND ENERGY METABOLISM OF EMBRYONIC AND LARVAL STEELHEAD TROUT

    EPA Science Inventory

    A study was conducted to determine the effects of technical grade sodium pentachlorophenate (Na-PCP) on the early developmental stages of the steelhead trout (Salmo gairdneri). In an experiment where embryos were exposed to Na-PCP from fertilization to hatching, 100% mortality oc...

  6. STABLE ISOTOPE SIGNATURES OF MUCUS OF STEELHEAD TROUT IN A CONTROLLED DIET SWITCH EXPERIMENT

    EPA Science Inventory

    Our work has shown that fish mucus can serve as a very rapid indicator of diet switching in fish. We performed diet switching studies of steelhead trout in a controlled hatchery setting using specially formulated low delta 15N signature and high delta 15N signature diets. To ou...

  7. SURVIVAL OF STEELHEAD TROUT (SALMO GAIRDNERI) EGGS, EMBRYOS, AND FRY IN AIR-SUPERSATURATED WATER

    EPA Science Inventory

    Egg, embryo, fry, and swim-up stages of steelhead trout (Salmo gairdneri) were exposed to water at total gas saturation levels ranging from 130 to 115%. Eggs, embryos, and newly hatched fry were not affected at 126.7%, but at about day 16 posthatch when the fish began swimming up...

  8. Kelt Reconditioning: A Research Project to Enhance Iteroparity in Columbia Basin Steelhead (Oncorhynchus mykiss), 2004 Annual Report.

    SciTech Connect

    Hatch, Douglas R.; Branstetter, Ryan; Whiteaker, John

    2004-11-01

    Iteroparity, the ability to repeat spawn, is a life history strategy that is expressed by some species from the family Salmonidae. Rates of repeat spawning for post-development Columbia River steelhead Oncorhynchus mykiss populations range from 1.6 to 17%. It is expected that currently observed iteroparity rates for wild steelhead in the Basin are severely depressed due to development and operation of the hydropower system and various additional anthropogenic factors. Increasing the expression of historical repeat spawning rates using fish culturing methods could be a viable technique to assist the recovery of depressed steelhead populations, and could help reestablish this naturally occurring life history trait. Reconditioning is the process of culturing post-spawned fish (kelts) in a captive environment until they are able to reinitiate feeding, growth, and redevelop mature gonads. Kelt reconditioning techniques were initially developed for Atlantic salmon Salmo salar and sea-trout S. trutta. The recent Endangered Species Act listing of many Columbia River Basin steelhead populations has prompted interest in developing reconditioning methods for wild steelhead populations within the Basin. To test kelt steelhead reconditioning as a potential recovery tool, wild emigrating steelhead kelts were placed into one of three study groups (direct capture and transport, short-term reconditioning, or long-term reconditioning). Steelhead kelts from the Yakima River were collected at the Chandler Juvenile Monitoring Facility (CJMF, located on the Yakima River at river kilometer 75.6) from 15 March to 21 June 2004. In total, 842 kelts were collected for reconditioning at Prosser Hatchery. Captive specimens represented 30.5% (842 of 2,755) of the entire 2003-2004 Yakima River wild steelhead population, based on fish ladder counts at Prosser Dam. All steelhead kelts were reconditioned in 20-foot circular tanks, and fed freeze-dried krill initially or for the duration of the

  9. The Response of a Steelhead Trout Population to Wildfire at the Landscape Scale

    NASA Astrophysics Data System (ADS)

    Boughton, D. A.

    2012-12-01

    Wildfire is a prevalent disturbance of watersheds that impacts stream habitats and fish abundance, by direct removal of riparian vegetation and indirect effects on sediment regimes and water quality. Individual studies at the reach scale of the fish Oncorhynchus mykiss (steelhead trout) after wildfire show that habitat- and population-response is highly context dependent, suggesting broad-scale heterogeneity in effects of wildfire, possibly linked to fluvial processes. Here I report the results of a novel study design that examined wildfire response of O. mykiss and its habitat condition at 26 reaches sampled from a stream system heavily burned during the 2008 Indians/Basin Complex Fire in the central California chaparral. Proportional decline in juvenile fish abundances in the year after the wildfire were large but spatially heterogeneous (ranging by 2 orders of magnitude). Influence diagrams suggested that the major impact of the fire on the fish was not direct impacts on riparian vegetation (which were quite minor), but indirect impacts via pulses of fine sediment into channels the following winter. Abundance at some sites increased after the fire; the largest increases were not outside (downstream of) the burned area, but rather were in headwater reaches inside the burned area. In the year after the wildfire, fish abundance rebounded, with magnitude of rebound nearly proportional to the previous year's decline at most sites, suggesting rapid recovery of habitat quality and population recruitment. This study illustrates the importance of spatial structure and fluvial-process diversity for the rapid recovery of a fish after an intense wildfire.

  10. A comparison of genetic variation between an anadromous steelhead, Oncorhynchus mykiss, population and seven derived populations sequestered in freshwater for 70 years

    USGS Publications Warehouse

    Thrower, F.; Guthrie, C., III; Nielsen, J.; Joyce, J.

    2004-01-01

    In 1926 cannery workers from the Wakefield Fisheries Plant at Little Port Walter in Southeast Alaska captured small trout, Oncorhynchus mykiss, from a portion of Sashin Creek populated with a wild steelhead (anadromous O. mykiss) run. They planted them into Sashin Lake which had been fishless to that time and separated from the lower stream by two large waterfalls that prevented upstream migration of any fish. In 1996 we sampled adult steelhead from the lower creek and juvenile O. mykiss from an intermediate portion of the creek, Sashin Lake, and five lakes that had been stocked with fish from Sashin Lake in 1938. Tissue samples from these eight populations were compared for variation in: microsatellite DNA at 10 loci; D-loop sequences in mitochondrial DNA; and allozymes at 73 loci known to be variable in steelhead. Genetic variability was consistently less in the Sashin Lake population and all derived populations than in the source anadromous population. The cause of this reduction is unknown but it is likely that very few fish survived to reproduce from the initial transplant in 1926. Stockings of 50-85 fish into five other fishless lakes in 1938 from Sashin Lake did not result in a similar dramatic reduction in variability. We discuss potential explanations for the observed patterns of genetic diversity in relation to the maintenance of endangered anadromous O. mykiss populations in freshwater refugia.

  11. Gyrodactylid Ectoparasites in a Population of Rainbow Trout (Oncorhynchus mykiss)

    PubMed Central

    Garcia, Rachel L; Hansen, Adam G; Chan, Maia M; Sanders, George E

    2014-01-01

    A colony of rainbow trout (Oncorhynchus mykiss) in a decentralized aquatic animal facility was noted to have an increase in morbidity and mortality (from 4 or 5 fish each month to 3 or 4 fish daily) approximately 2 wk after experimental procedures began. The primary clinical signs were erratic swimming behavior and ‘flashing’ of fish against surfaces within housing enclosures. Moribund and normal rainbow trout were presented alive for diagnostic evaluation; samples of water from housing enclosures were provided for water quality assessment. The trout were determined to be infected with gyrodactylids, a common monogenean ectoparasite of the skin and gills in both marine and freshwater fish. This case report describes the diagnosis, pathology, and treatment of gyrodactylids and husbandry modifications associated with the resolution of this clinical aquatic-animal case. PMID:24411786

  12. Virulence of Flavobacterium columnare genomovars in rainbow trout Oncorhynchus mykiss.

    PubMed

    Evenhuis, Jason P; LaFrentz, Benjamin R

    2016-08-01

    Flavobacterium columnare is the causative agent of columnaris disease and is responsible for significant economic losses in aquaculture. F. columnare is a Gram-negative bacterium, and 5 genetic types or genomovars have been described based on restriction fragment length polymorphism of the 16S rRNA gene. Previous research has suggested that genomovar II isolates are more virulent than genomovar I isolates to multiple species of fish, including rainbow trout Oncorhynchus mykiss. In addition, improved genotyping methods have shown that some isolates previously classified as genomovar I, and used in challenge experiments, were in fact genomovar III. Our objective was to confirm previous results with respect to genomovar II virulence, and to determine the susceptibility of rainbow trout to other genomovars. The virulence of 8 genomovar I, 4 genomovar II, 3 genomovar II-B, and 5 genomovar III isolates originating from various sources was determined through 3 independent challenges in rainbow trout using an immersion challenge model. Mean cumulative percent mortality (CPM) of ~49% for genomovar I isolates, ~1% for genomovar II, ~5% for the II-B isolates, and ~7% for the III isolates was observed. The inability of genomovar II isolates to produce mortalities in rainbow trout was unanticipated based on previous studies, but may be due to a number of factors including rainbow trout source and water chemistry. The source of fish and/or the presence of sub-optimal environment may influence the susceptibility of rainbow trout to different F. columnare genomovars. PMID:27503917

  13. Electronic tags and genetics explore variation in migrating steelhead kelts (oncorhynchus mykiss), Ninilchik river, Alaska

    USGS Publications Warehouse

    Nielsen, J.L.; Turner, S.M.; Zimmerman, C.E.

    2011-01-01

    Acoustic and archival tags examined freshwater and marine migrations of postspawn steelhead kelts (Oncorhynchus mykiss) in the Ninilchik River, Alaska, USA. Postspawn steelhead were captured at a weir in 2002-2005. Scale analysis indicated multiple migratory life histories and spawning behaviors. Acoustic tags were implanted in 99 kelts (2002-2003), and an array of acoustic receivers calculated the average speed of outmigration, timing of saltwater entry, and duration of residency in the vicinity of the river mouth. Ocean migration data were recovered from two archival tags implanted in kelts in 2004 (one male and one female). Archival tags documented seasonal differences in maximum depth and behavior with both fish spending 97% of time at sea <6 m depth (day and night). All study fish were double tagged with passive integrated transponder (PIT) tags implanted in the body cavity. Less than 4% of PIT tags were retained in postspawn steelhead. Molecular genetics demonstrated no significant differences in genetic population structure across years or among spawning life history types, suggesting a genetically panmictic population with highly diverse life history characteristics in the Ninilchik River.

  14. Comparative diets of subyearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) in the Salmon River, New York

    USGS Publications Warehouse

    Johnson, J.H.

    2007-01-01

    Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) have established naturalized populations throughout the Great Lakes. Young-of-year of these species occur sympatrically for about one month in Lake Ontario tributaries. This study examined the diets of subyearling Chinook salmon and steelhead relative to available food in the Salmon River, New York. Terrestrial invertebrates and trichopterans were the major prey of Chinook salmon, whereas steelhead fed primarily on baetid nymphs and chironomid larvae. Diet overlap was low (0.45) between the species. The diet of Chinook was closely associated to the composition of the drift (0.88). Steelhead diet drew equally from the drift and benthos during the first year of the study, but more closely matched the benthos during the second year. Differences in prey selection, perhaps associated with differences in fish size, in addition to apparent differences in feeding mode (drift versus benthic), likely reduce competitive interactions between these species.

  15. Relative sensitivity of bull trout (Salvelinus confluentus) and rainbow trout (Oncorhynchus mykiss) to acute copper toxicity.

    PubMed

    Hansen, James A; Lipton, Josh; Welsh, Paul G

    2002-03-01

    Bull trout (Salvelinus confluentus) were recently listed as threatened in the United States under the federal Endangered Species Act. Past and present habitat for this species includes waterways contaminated with heavy metals released from mining activities. Because the sensitivity of this species to copper was previously unknown, we conducted acute copper toxicity tests with bull and rainbow trout (Oncorhynchus mykiss) in side-by-side comparison tests. Bioassays were conducted using water at two temperatures (8 degrees C and 16 degrees C) and two hardness levels (100 and 220 mg/L as CaCO3). At a water hardness of 100 mg/L, both species were less sensitive to copper when tested at 16 degrees C compared to 8 degrees C. The two species had similar sensitivity to copper in 100-mg/ L hardness water, but bull trout were 2.5 to 4 times less sensitive than rainbow trout in 220-mg/L hardness water. However, when our results were viewed in the context of the broader literature on rainbow trout sensitivity to copper, the sensitivities of the two species appeared similar. This suggests that adoption of toxicity thresholds that are protective of rainbow trout would be protective of bull trout; however, an additional safety factor may be warranted because of the additional level of protection necessary for this federally threatened species. PMID:11878477

  16. Rainbow trout (Oncorhynchus mykiss) invasion and the spread of hybridization with native westslope cutthroat trout (Oncorhynchus clarkii lewisi)

    USGS Publications Warehouse

    Boyer, M.C.; Muhlfeld, C.C.; Allendorf, F.W.

    2008-01-01

    We analyzed 13 microsatellite loci to estimate gene flow among westslope cutthroat trout, Oncorhynchus clarkii lewisi, populations and determine the invasion pattern of hybrids between native O. c. lewisi and introduced rainbow trout, Oncorhynchus mykiss, in streams of the upper Flathead River system, Montana (USA) and British Columbia (Canada). Fourteen of 31 sites lacked evidence of O. mykiss introgression, and gene flow among these nonhybridized O. c. lewisi populations was low, as indicated by significant allele frequency divergence among populations (?ST = 0.076, ?ST = 0.094, P < 0.001). Among hybridized sites, O. mykiss admixture declined with upstream distance from a site containing a hybrid swarm with a predominant (92%) O. mykiss genetic contribution. The spatial distribution of hybrid genotypes at seven diagnostic microsatellite loci revealed that O. mykiss invasion is facilitated by both long distance dispersal from this hybrid swarm and stepping-stone dispersal between hybridized populations. This study provides an example of how increased straying rates in the invasive taxon can contribute to the spread of extinction by hybridization and suggests that eradicating sources of introgression may be a useful conservation strategy for protecting species threatened with genomic extinction. ?? 2008 NRC.

  17. Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, Oncorhynchus mykiss

    USGS Publications Warehouse

    Hitt, Nathaniel P.; Frissell, Christopher A.; Muhlfeld, Clint C.; Fred W. Allendorf

    2003-01-01

    We examined spatial and temporal patterns of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, O. mykiss, in streams of the Flathead River system in Montana, U.S.A. We detected hybridization in 24 of 42 sites sampled from 1998 to 2001. We found new Oncorhynchus mykiss introgression in seven of 11 sample populations that were determined to be nonhybridized in 1984. Patterns of spatial autocorrelation and linkage disequilibrium indicated that hybridization is spreading among sites and is advancing primarily via post-F1 hybrids. Although hybridized populations were distributed widely throughout the study area, the genetic contribution from O. mykiss decreased with increasing upstream distance from the Flathead River mainstem, suggesting that O. mykiss introgression is spreading in an upstream direction. The spread of hybridization may be constrained more by demographic than by environmental factors, given that (i) hybridized populations generally encompassed the range of environmental variability in nonhybridized populations, and (ii) hybridization status was more strongly associated with neighborhood statistics than measured environmental gradients.

  18. Landscape scale measures of steelhead (Oncorhynchus mykiss) bioenergetic growth rate potential in Lake Michigan and comparison with angler catch rates

    USGS Publications Warehouse

    Hook, T.O.; Rutherford, E.S.; Brines, Shannon J.; Geddes, C.A.; Mason, D.M.; Schwab, D.J.; Fleischer, G.W.

    2004-01-01

    The relative quality of a habitat can influence fish consumption, growth, mortality, and production. In order to quantify habitat quality, several authors have combined bioenergetic and foraging models to generate spatially explicit estimates of fish growth rate potential (GRP). However, the capacity of GRP to reflect the spatial distributions of fishes over large areas has not been fully evaluated. We generated landscape scale estimates of steelhead (Oncorhynchus mykiss) GRP throughout Lake Michigan for 1994-1996, and used these estimates to test the hypotheses that GRP is a good predictor of spatial patterns of steelhead catch rates. We used surface temperatures (measured with AVHRR satellite imagery) and acoustically measured steelhead prey densities (alewife, Alosa pseudoharengus) as inputs for the GRP model. Our analyses demonstrate that potential steelhead growth rates in Lake Michigan are highly variable in both space and time. Steelhead GRP tended to increase with latitude, and mean GRP was much higher during September 1995, compared to 1994 and 1996. In addition, our study suggests that landscape scale measures of GRP are not good predictors of steelhead catch rates throughout Lake Michigan, but may provide an index of interannual variation in system-wide habitat quality.

  19. Genome-wide association reveals genetic basis for the propensity to migrate in wild populations of rainbow and steelhead trout.

    PubMed

    Hecht, Benjamin C; Campbell, Nathan R; Holecek, Dean E; Narum, Shawn R

    2013-06-01

    Little is known of the genetic basis of migration despite the ecological benefits migratory species provide to their communities and their rapid global decline due to anthropogenic disturbances in recent years. Using next-generation sequencing of restriction-site-associated DNA (RAD) tags, we genotyped thousands of single nucleotide polymorphisms (SNPs) in two wild populations of migratory steelhead and resident rainbow trout (Oncorhynchus mykiss) from the Pacific Northwest of the United States. One population maintains a connection to the sea, whereas the other population has been sequestered from its access to the ocean for more than 50 years by a hydropower dam. Here we performed a genome-wide association study to identify 504 RAD SNP markers from several genetic regions that were associated with the propensity to migrate both within and between the populations. Our results corroborate those in previous quantitative trait loci studies and provide evidence for additional loci associated with this complex migratory life history. Our results suggest a complex multi-genic basis with several loci of small effect distributed throughout the genome contributing to migration in this species. We also determined that despite being sequestered for decades, the landlocked population continues to harbour genetic variation associated with a migratory life history and ATPase activity. Furthermore, we demonstrate the utility of genotyping-by-sequencing and how RAD-tag SNP data can be readily compared between studies to investigate migration within this species. PMID:23106605

  20. Ecosystem experiment reveals benefits of natural and simulated beaver dams to a threatened population of steelhead (Oncorhynchus mykiss)

    PubMed Central

    Bouwes, Nicolaas; Weber, Nicholas; Jordan, Chris E.; Saunders, W. Carl; Tattam, Ian A.; Volk, Carol; Wheaton, Joseph M.; Pollock, Michael M.

    2016-01-01

    Beaver have been referred to as ecosystem engineers because of the large impacts their dam building activities have on the landscape; however, the benefits they may provide to fluvial fish species has been debated. We conducted a watershed-scale experiment to test how increasing beaver dam and colony persistence in a highly degraded incised stream affects the freshwater production of steelhead (Oncorhynchus mykiss). Following the installation of beaver dam analogs (BDAs), we observed significant increases in the density, survival, and production of juvenile steelhead without impacting upstream and downstream migrations. The steelhead response occurred as the quantity and complexity of their habitat increased. This study is the first large-scale experiment to quantify the benefits of beavers and BDAs to a fish population and its habitat. Beaver mediated restoration may be a viable and efficient strategy to recover ecosystem function of previously incised streams and to increase the production of imperiled fish populations. PMID:27373190

  1. Ecosystem experiment reveals benefits of natural and simulated beaver dams to a threatened population of steelhead (Oncorhynchus mykiss).

    PubMed

    Bouwes, Nicolaas; Weber, Nicholas; Jordan, Chris E; Saunders, W Carl; Tattam, Ian A; Volk, Carol; Wheaton, Joseph M; Pollock, Michael M

    2016-01-01

    Beaver have been referred to as ecosystem engineers because of the large impacts their dam building activities have on the landscape; however, the benefits they may provide to fluvial fish species has been debated. We conducted a watershed-scale experiment to test how increasing beaver dam and colony persistence in a highly degraded incised stream affects the freshwater production of steelhead (Oncorhynchus mykiss). Following the installation of beaver dam analogs (BDAs), we observed significant increases in the density, survival, and production of juvenile steelhead without impacting upstream and downstream migrations. The steelhead response occurred as the quantity and complexity of their habitat increased. This study is the first large-scale experiment to quantify the benefits of beavers and BDAs to a fish population and its habitat. Beaver mediated restoration may be a viable and efficient strategy to recover ecosystem function of previously incised streams and to increase the production of imperiled fish populations. PMID:27373190

  2. Sensory analysis of rainbow trout, oncorhynchus mykiss, fed enriched black soldier fly prepupae, hermetia illucens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A growth trial and fillet sensory analysis were conducted to examine the effects of replacing dietary fish meal with black soldier fly (BSF) prepupae, Hermetia illucens, in rainbow trout, Oncorhynchus mykiss. A practical-type trout diet was formulated to contain 45% protein; four test diets were dev...

  3. Case report of an unusual heart abnormality in Rainbow trout (Oncorhynchus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An unusual heart abnormality in rainbow trout Oncorhynchus mykiss was recently observed. During the course of a standard hydrogen peroxide treatment (100 ppm) of production rainbow trout (mean weight, 2-3 g) affected with an external bacterial infection, a small percentage of fish exhibited morbidi...

  4. Toxicokinetics of perfluorooctane sulfonate in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Consoer, Daniel M; Hoffman, Alex D; Fitzsimmons, Patrick N; Kosian, Patricia A; Nichols, John W

    2016-03-01

    Rainbow trout (Oncorhynchus mykiss) confined to respirometer-metabolism chambers were dosed with perfluorooctane sulfonate (PFOS) by intra-arterial injection and sampled to obtain concentration time-course data for plasma and either urine or expired water. The data were then analyzed using a 2-compartment clearance-volume model. Renal and branchial clearance rates (mL/d/kg) determined for all experiments averaged 19% and 81% of total clearance, respectively. Expressed as mean values for all experiments, the steady-state volume of distribution was 277 mL/kg and the terminal half-life was 86.8 d. Additional animals were exposed to PFOS in water, resulting in an average calculated branchial uptake efficiency of 0.36%. The renal clearance rate determined in the present study is approximately 75 times lower than that determined in earlier studies with perfluorooctanoate (PFOA). Previously, it was suggested that PFOA is a substrate for membrane transporters in the trout kidney. The present study suggests that glomerular filtration may be sufficient to explain the observed renal clearance rate for PFOS, although a role for membrane transporters cannot be ruled out. These findings demonstrate that models developed to predict the bioaccumulation of perfluoroalkyl acids by fish must account for differences in renal clearance of individual compounds. Environ Toxicol Chem 2016;35:717-727. © 2015 SETAC. PMID:26332333

  5. Effects of pyrethroid insecticides in urban runoff on Chinook salmon, steelhead trout, and their invertebrate prey.

    PubMed

    Weston, Donald P; Schlenk, Daniel; Riar, Navneet; Lydy, Michael J; Brooks, Marjorie L

    2015-03-01

    Pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or directly by toxicity to the fish themselves. In support of a study on pyrethroid impacts to Chinook salmon and steelhead trout in the American River (Sacramento, California, USA), 96-h median effective concentration (EC50) and median lethal concentration (LC50) values for the pyrethroid bifenthrin were determined for taxa not traditionally used for toxicity testing but of interest as salmonid prey, including a chironomid, caddisflies, mayflies, and stoneflies. A laboratory was constructed on the banks of the American River to expose macroinvertebrates, Chinook salmon, and steelhead trout to flow-through river water containing urban runoff during storm events. Bifenthrin from urban runoff was found in river water following 5 rain events, reaching 14.6 ng/L. Mortality to the exposed salmonids was not observed, and sublethal effects were not seen in vitellogenin or sex steroid levels. Indirect effects via toxicity to salmonid prey are possible. Mortality to Hyalella azteca, a potential prey, was observed in every event tested, and peak bifenthrin concentrations were comparable to the 96-h EC50 of the caddisfly, Hydropsyche sp., the most important prey species on a biomass basis for American River Chinook salmon. The other invertebrates tested had EC50s exceeding bifenthrin concentrations seen in the American River, though could potentially be at risk at concentrations previously reported in smaller urban tributaries. Environ Toxicol Chem 2015;34:649-657. © 2014 SETAC. PMID:25545717

  6. STRESS-INDUCED TRANSMISSON OF 'YERSINIA RUCKERI' INFECTION FROM CARRIERS TO RECIPIENT STEELHEAD TROUT 'SALMO GAIRDNERI' RICHARDSON

    EPA Science Inventory

    The transmission of Yersinia ruckeri has been investigated in steelhead trout using asymptomatic carriers of the causative bacterium of enteric redmouth disease. It was found that unstressed carrier fish did not transmit the bacterium to recipient fish to cause either an epizooti...

  7. Fate of Tetracapsuloides bryosalmonae (Myxozoa) after infection of brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss

    PubMed Central

    Kumar, Gokhlesh; Abd-Elfattah, Ahmed; Saleh, Mona; El-Matbouli, Mansour

    2014-01-01

    Tetracapsuloides bryosalmonae (Myxozoa) is the causative agent of proliferative kidney disease in salmonids. We assessed differences in intensity of T. bryosalmonae infection between brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss from the clinical phase of infection onwards. Specific pathogen-free fish were exposed to T. bryosalmonae spores under controlled laboratory conditions and sampled at 6, 8, 10, 12, 14, and 17 wk post exposure (wpe), and the transmission of T. bryosalmonae from infected fish to the bryozoan Fredericella sultana was observed. Parasite load was determined in fish kidneys by quantitative real-time PCR (qRT-PCR), and parasite stages were detected in kidney, liver, and spleen tissues at different time points by immunohistochemistry. T. bryosalmonae was successfully transmitted from infected brown trout to F. sultana colonies but not from infected rainbow trout. Body length and weight of infected brown trout did not differ significantly from control brown trout during all time points, while length and weight of infected rainbow trout differed significantly compared to controls from 10 to 17 wpe. qRT-PCR revealed that parasite load was significantly higher in kidneys of brown trout compared with rainbow trout. Immunohistochemistry showed high numbers of intra-luminal stages (sporogonic stages) in kidneys of brown trout with low numbers of pre-sporogonic stages. Sporogonic stages were not seen in kidneys of rainbow trout; only high numbers of pre-sporogonic stages were detected. Numbers of pre-sporogonic stages were low in the spleen and liver of brown trout but high in rainbow trout. These data confirmed that there are differences in the development and infection progress of T. bryosalmonae between brown trout and rainbow trout. PMID:24270019

  8. Comparison of biochemical parameters of rainbow trout (Oncorhynchus mykiss) reared in two different trout farms'

    NASA Astrophysics Data System (ADS)

    Karatas, Tayfun

    2016-04-01

    The aim of this study was to compare biochemical parameters of cultured rainbow trouts (Oncorhynchus mykiss, Walbaum, 1972) reared in two different trout farms' (Agri and Erzurum). The average weights of fish were 150±10gr for first station (Agri), 230±10gr for second station (Erzurum). Fishes used in research were randomly caught from pools, and fifteen pieces were used for each group. Fishes were fed with commercial trout feed with 45-50% crude protein twice a day. The levels of AST, ALT, LDL, total cholesterol and triglyceride in the second station (Erzurum) were found to be higher (p<0.05) than that of first station (Agri). Whereas, the levels of HDL in the second station (Erzurum) were found to be lower (p<0.05) than that of first station (Agri). Differences in the levels of total cholesterol and AST, ALT, HDL, LDL, triglyceride may be associated with size, sex, sexual maturity and environmental conditions (temperature, pH, hardness and dissolved oxygen).

  9. Evaluation of strobe lights to reduce turbine entrainment of juvenile steelhead (Oncorhynchus mykiss) at Cowlitz Falls Dam, Washington

    USGS Publications Warehouse

    2009-01-01

    We conducted a radiotelemetry evaluation to determine if strobe lights could be used to decrease turbine entrainment of juvenile steelhead (Oncorhynchus mykiss) at Cowlitz Falls Dam, Washington. We found that radio-tagged juvenile steelhead approached and entered two spillbays (one lighted, one unlighted) in equal proportions. However, the presence of strobe lights was associated with decreased spillbay residence time of juvenile steelhead and increased passage through induction slots (secondary turbine intakes located upstream of the ogee on the spillway). Mean residence time of tagged fish inside the lighted spillbay was 14 min compared to 62 min inside the unlighted spillbay. Radio-tagged steelhead passed through induction slots at a higher proportion in the lighted spillbay (55%) than in the unlighted spillbay (26%). Recent studies have suggested that strobe lights can induce torpor in juvenile salmonids. We believe that strobe light exposure affected fish in our study at a location where they were susceptible to high flows thereby reducing mean residence time and increasing the proportion of tagged fish entering induction slots in the lighted spillbay. Our results suggest that factors such as deployment location, exposure, and flow are important variables that should be considered when evaluating strobe lights as a potential fish-deterring management tool.

  10. Tolerance to gas supersaturation in freshwater and seawater by steelhead trout (Salmo gairdneri)

    USGS Publications Warehouse

    Bouck, G.R.; King, R.E.

    1983-01-01

    The euryhaline status of steelhead trout, Salmo gairdneri, smolts was challenged in sea water for 2 weeks after which half of the total fish population was returned to fresh water. Acclimation continued and created two test populations in 29%osea water and fresh water. Subsequently these fish were exposed in fresh water or sea water to approximately equal hyperbaric dissolved total gas pressures (ΔP) of 190 mm Hg or about 125% of barometric pressure. Sea water was easier to supersaturate with air and required only about 10% of the entrained air which was required in fresh water at the same temperature and pressure. Mean time to first mortality was sooner in sea water. Mean times to mortality (10–50%) were not significantly different between fresh water and sea water, but there was a noticeable trend for longer survival in fresh water.

  11. Genetic differences in growth and survival of juvenile hatchery and wild steelhead trout, Salmo gairdneri

    USGS Publications Warehouse

    Reisenbichler, R.R.; McIntyre, J.D.

    1997-01-01

    Relative growth and survival of offspring from matings of hatchery and wild Deschutes River (Oregon) summer steelhead trout, Salmo gairdneri, were measured to determine if hatchery fish differ genetically from wild fish in traits that can affect the stock–recruitment relationship of wild populations. Sections of four natural streams and a hatchery pond were each stocked with genetically marked (lactate dehydrogenase genotypes) eyed eggs or unfed swim-up fry from each of three matings: hatchery × hatchery (HH), hatchery × wild (HW), and wild × wild (WW). In streams, WW fish had the highest survival and HW fish the highest growth rates when significant differences were found; in the hatchery pond, HH fish had the highest survival and growth rates. The hatchery fish were genetically different from wild fish and when they interbreed with wild fish may reduce the number of smolts produced. Hatchery procedures can be modified to reduce the genetic differences between hatchery and wild fish.

  12. Muscle wound healing in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Schmidt, J G; Andersen, E W; Ersbøll, B K; Nielsen, M E

    2016-01-01

    We followed the progression of healing of deep excisional biopsy punch wounds over the course of 365 days in rainbow trout (Oncorhynchus mykiss) by monitoring visual wound healing and gene expression in the healing muscle at regular intervals (1, 3, 7, 14, 38 and 100 days post-wounding). In addition, we performed muscle texture analysis one year after wound infliction. The selected genes have all previously been investigated in relation to vertebrate wound healing, but only few specifically in fish. The selected genes were interleukin (IL)-1β, IL-6, transforming growth factor (TGF)-β1 and -β3, matrix metalloproteinase (MMP) -9 and -13, inducible nitric oxide synthase (iNOS), fibronectin (FN), tenascin-C (TN-C), prolyl 4-hydroxylase α1-chain (P4Hα1), lysyl oxidase (LOX), collagen type I α1-chain (ColIα1), CD41 and CD163. Wound healing progressed slowly in the presented study, which is at least partially due to the low temperature of about 8.5 °C during the first 100 days. The inflammation phase lasted more than 14 days, and the genes relating to production and remodeling of new extracellular matrix (ECM) exhibited a delayed but prolonged upregulation starting 1-2 weeks post-wounding and lasting until at least 100 days post-wounding. The gene expression patterns and histology reveal limited capacity for muscle regeneration in rainbow trout, and muscle texture analyses one year after wound infliction confirm that wounds heal with fibrosis. At 100 dpw epidermis had fully regenerated, and dermis partially regenerated. Scales had not regenerated even after one year. CD163 is a marker of "wound healing"-type M2c macrophages in mammals. M2 macrophage markers are as yet poorly described in fish. The pattern of CD163 expression in the present study is consistent with the expected timing of presence of M2c macrophages in the wound. CD163 may thus potentially prove a valuable marker of M2 macrophages - or a subset hereof - in fish. We subjected a group of fish to

  13. Transportation of chinook salmon, Oncorhynchus tshawytscha, and steelhead, Salmo gairdneri, smolts in the Columbia River and effects on adult returns

    SciTech Connect

    Ebel, W.J.

    1980-04-01

    Chinook salmon, Oncorhynchus tshawytscha, and steelhead, Salmo gairdneri, were captured at Little Goose Dam in the Snake River during their seaward migration and transported 400 km downstream to the lower Columbia River below Bonneville Dam. Their survival was increased from 1.1 to 15 times as compared with control fish which passed by seven mainstem low-level dams and reservoirs. Variations in survival were mainly dependent on species and environmental conditions in the river during the period fish were transported. The homing ability of the adult fish was not significantly diminished; less than 0.2% of strays occurred among adult returns from groups transported. Transportation did not affect ocean age or size of returning adult steelhead, but ocean age of returning adult chinook salmon may have been affected. Steelhead returned to Little Goose Dam at a substantially higher rate (1.4 to 2.7%) than chinook salmon (0.1 to 0.8%) from groups transported. The timing of adult returns of both species to Little Goose Dam was not related to the time of capture and downstream release of smolts.

  14. Quantitative genetics of migration-related traits in rainbow and steelhead trout.

    PubMed

    Hecht, Benjamin C; Hard, Jeffrey J; Thrower, Frank P; Nichols, Krista M

    2015-05-01

    Rainbow trout (Oncorhynchus mykiss) exhibit remarkable life history diversity throughout their native range, and among the most evident is variation in migratory propensity. Although some populations and ecotypes will remain resident in freshwater habitats throughout their life history, others have the ability to undertake tremendous marine migrations. Those that migrate undergo a suite of behavioral, morphological, and physiological adaptations in a process called smoltification. We describe a quantitative genetic analysis of 22 growth, size, and morphological traits in addition to overall life history classification (resident or migrant) over the temporal process of smoltification in a large multi-generation experimental pedigree (n = 16,139) of migratory and resident rainbow trout derived from a wild population, which naturally segregates for migratory propensity. We identify significant additive genetic variance and covariance among the suite of traits that make up a component of the migratory syndrome in this species. Additionally, we identify high heritability estimates for the life history classifications and observe a strong negative genetic correlation between the migratory and resident life history trajectories. Given the large heritability estimates of all of the traits that segregate between migratory and resident rainbow trout, we conclude that these traits can respond to selection. However, given the high degree of genetic correlation between these traits, they do not evolve in isolation, but rather as a suite of coordinated characters in a predictable manner. PMID:25784164

  15. Quantitative Genetics of Migration-Related Traits in Rainbow and Steelhead Trout

    PubMed Central

    Hecht, Benjamin C.; Hard, Jeffrey J.; Thrower, Frank P.

    2015-01-01

    Rainbow trout (Oncorhynchus mykiss) exhibit remarkable life history diversity throughout their native range, and among the most evident is variation in migratory propensity. Although some populations and ecotypes will remain resident in freshwater habitats throughout their life history, others have the ability to undertake tremendous marine migrations. Those that migrate undergo a suite of behavioral, morphological, and physiological adaptations in a process called smoltification. We describe a quantitative genetic analysis of 22 growth, size, and morphological traits in addition to overall life history classification (resident or migrant) over the temporal process of smoltification in a large multi-generation experimental pedigree (n = 16,139) of migratory and resident rainbow trout derived from a wild population, which naturally segregates for migratory propensity. We identify significant additive genetic variance and covariance among the suite of traits that make up a component of the migratory syndrome in this species. Additionally, we identify high heritability estimates for the life history classifications and observe a strong negative genetic correlation between the migratory and resident life history trajectories. Given the large heritability estimates of all of the traits that segregate between migratory and resident rainbow trout, we conclude that these traits can respond to selection. However, given the high degree of genetic correlation between these traits, they do not evolve in isolation, but rather as a suite of coordinated characters in a predictable manner. PMID:25784164

  16. Mapping and expression of candidate genes for development rate in rainbow trout (Oncorhynchus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development rate has important implications for many aspects of an individual's biology. In rainbow trout (Oncorhynchus mykiss), a major QTL for embryonic development rate has been detected on chromosome 5, but at present, few candidate genes have been mapped to this region. This paucity of known ge...

  17. Effects of sex steroids on indices of protein turnover in rainbow trout (Oncorhynchus mykiss) white muscle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of 17-estradiol (E2), testosterone, and 5a-dihydrotestosterone (DHT) on protein turnover and proteolytic gene expression were determined in rainbow trout (Oncorhynchus mykiss) primary myocytes and white muscle tissue. E2 reduced rates of protein synthesis and increased rates of protein degr...

  18. Observations on side-swimming rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During a controlled 6-month study using six replicated water recirculation aquaculture systems (WRAS), it was observed that rainbow trout Oncorhynchus mykiss in all WRAS exhibited a higher-than-normal prevalence of side-swimming (i.e. controlled, forward swimming, but with misaligned orientation suc...

  19. Growth enhancement of rainbow trout (Oncorhynchus mykiss) by passive immunisation against somatostatin-14

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Juvenile rainbow trout (Oncorhynchus mykiss) were passively immunised against somatostatin-14 (SS-14) using an antibody originating from egg laying chicken (Gallus domesticus). Fish were immunised weekly (0, 7, 14, 21, 28, 35 d) with chicken egg yolk derived immunoglobulin (IgY) against SS-14 (1:25 ...

  20. Carnosine supplementation to an all-plant protein diet for rainbow trout (Oncorhynchus mykiss).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fishmeal may contain “unknown growth factors” that have yet to be identified for their physiological role. As fishmeal levels in rainbow trout (Oncorhynchus mykiss) feeds are reduced, the dietary loss of these compounds may contribute to growth reductions. One such compound, identified in fishmeal...

  1. CHARACTERIZATION AND MAPPING OF NINETEEN POLYMORPHIC MICROSATELLITE MARKERS FOR RAINBOW TROUT (ONCORHYNCHUS MYKISS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nineteen new polymorphic microsatellite markers were developed for QTL mapping and population genetics studies in rainbow trout (Oncorhynchus mykiss). The amount of polymorphism, percent heterozygosity, ability of each marker to amplify genomic DNA from other salmonids and two point linkage data wer...

  2. Inhibition of salt water survival and Na-K-ATPase elevation in steelhead trout (Salmo gairdneri) by moderate water temperatures

    USGS Publications Warehouse

    Adams, B. L.; Zaugg, W.S.; McLain, L. R.

    1975-01-01

    The steelhead trout metamorphosis from a freshwater parr to a sea water-tolerant smolt possessing the migration tendency was evaluated at six different growth temperatures ranging from 6 to 15 C during January through July. The highest temperature where a transformation was indicated was 11.3 C. By April fish reared at 6 C had elevated ATPase levels typical of smolts or migratory animals and showed 92% survival in sea water. Ten and 11.3 C-reared fish showed a short-lived elevation in ATPase in mid-April alone concurrently with 100% sea water survival at that time. Only in 6 C-reared animals did the salt water survival ability continue into May. High ATPase levels likewise were prolonged into May and June only in the 6 C-reared group. The data indicate that metamorphosis (and therefore successful migration) of juvenile steelhead trout is directly controlled by water temperature.

  3. Genetic characterization of hybridization and introgression between anadromous rainbow trout (oncorhynchus mykiss irideus) and coastal cutthroat trout (o. clarki clarki)

    USGS Publications Warehouse

    Young, W.P.; Ostberg, C.O.; Keim, P.; Thorgaard, G.H.

    2001-01-01

    Interspecific hybridization represents a dynamic evolutionary phenomenon and major conservation problem in salmonid fishes. In this study we used amplified fragment length polymorphisms (AFLP) and mitochondrial DNA (mtDNA) markers to describe the extent and characterize the pattern of hybridization and introgression between coastal rainbow trout (Oncorhynchus mykiss irideus) and coastal cutthroat trout (O. clarki clarki). Hybrid individuals were initially identified using principle coordinate analysis of 133 polymorphic AFLP markers. Subsequent analysis using 23 diagnostic AFLP markers revealed the presence of F1, rainbow trout backcross, cutthroat trout backcross and later-generation hybrids. mtDNA analysis demonstrated equal numbers of F1 hybrids with rainbow and cutthroat trout mtDNA indicating reciprocal mating of the parental types. In contrast, rainbow and cutthroat trout backcross hybrids always exhibited the mtDNA from the recurrent parent, indicating a male hybrid mating with a pure female. This study illustrates the usefulness of the AFLP technique for generating large numbers of species diagnostic markers. The pattern of hybridization raises many questions concerning the existence and action of reproductive isolating mechanisms between these two species. Our findings are consistent with the hypothesis that introgression between anadromous populations of coastal rainbow and coastal cutthroat trout is limited by an environment-dependent reduction in hybrid fitness.

  4. Quantitative evaluation of macrophage aggregates in brook trout Salvelinus fontinalis and rainbow trout Oncorhynchus mykiss

    USGS Publications Warehouse

    Schwindt, Adam R.; Truelove, Nathan; Schreck, Carl B.; Fournie, John W.; Landers, Dixon H.; Kent, Michael L.

    2006-01-01

    Macrophage aggregates (MAs) occur in various organs of fishes, especially the kidney, liver and spleen, and contain melanin, ceroid/lipofuscin and hemosiderin pigments. They have been used as indicators of a number of natural and anthropogenic stressors. Macrophage aggregates occur in salmonids but are poorly organized, irregularly shaped, and are generally smaller than those in derived teleosts. These features complicate quantification, and thus these fishes have seldom been used in studies correlating MAs with environmental stressors. To alleviate these complications, we developed color filtering algorithms for use with the software package ImagePro Plus® (Media Cybernetics) that select and quantify pigmented area (i.e. colors ranging from gold to brown to black) in tissue sections. Image analysis results compared well with subjective scoring when tested on brook trout Salvelinus fontinalis and rainbow trout Oncorhynchus mykiss captured from high-elevation lakes or hatcheries. Macrophage aggregate pigments correlated positively with age and negatively with condition factor. Within individual fish, pigmentation correlated positively among organs, suggesting that the kidney, liver or spleen are suitable indicator organs. In age-matched fishes, MA pigments were not different between hatcheries and lakes in the organs examined. Between lakes, differences in pigments were observed in the kidney and spleen, but were not explained by age, condition factor, sex or maturation state. Our results indicate that quantification of the area occupied by MA pigments is an efficient and accurate means of evaluating MAs in salmonid organs and that organ pigmentation correlates with age and condition factor, as seen in studies with more derived fishes. 

  5. Evaluation of angler effort and harvest of rainbow trout (Oncorhynchus mykiss), Lake Scanewa, Washington, 2010

    USGS Publications Warehouse

    Liedtke, Theresa L.; Kock, Tobias J.; Ekstrom, Brian K.; Tomka, Ryan G.; Rondorf, Dennis W.

    2011-01-01

    A creel evaluation was conducted in Lake Scanewa, a reservoir on the Cowlitz River, to monitor catch rates of rainbow trout (Oncorhynchus mykiss) and determine if the trout fishery was having negative impacts on juvenile anadromous salmon (Oncorhynchus spp.) in the system. The trout fishery, which is supported by releases of 20,000 fish (2 fish per pound) per year from June to August, was developed to mitigate for the construction of the Cowlitz Falls Dam in 1994. The trout fishery has a target catch rate of at least 0.50 fish per hour. Interviews with 1,214 anglers during the creel evaluation found that most anglers targeted rainbow trout (52 percent) or Chinook and coho salmon (48 percent). The interviewed anglers caught a total of 1,866 fish, most of which were rainbow trout (1,213 fish; 78 percent) or coho salmon (311 fish; 20 percent). We estimated that anglers spent 17,365 hours fishing in Lake Scanewa from June to November 2010. Catch rates for boat anglers (1.39 fish per hour) exceeded the 0.50 fish per hour target, whereas catch rates for shore anglers (0.35 fish per hour) fell short of the goal. The combined catch rates for all trout anglers in the reservoir were 0.96 fish per hour. We estimated that anglers harvested 7,584 (95 percent confidence interval = 2,795-12,372 fish) rainbow trout during the study period and boat anglers caught more fish than shore anglers (5,975 and 1,609 fish, respectively). This estimate suggests that more than 12,000 of the 20,000 rainbow trout released into Lake Scanewa during 2010 were not harvested, and could negatively impact juvenile salmon in the reservoir through predation or competition. We examined 1,236 stomach samples from rainbow trout and found that 2.1 percent (26 fish) of these samples contained juvenile fish. Large trout (greater than 300 millimeters) had a higher incidence of predation than small trout (less than 300 millimeters; 8.50 and 0.06 percent, respectively). A total of 39 fish were found in rainbow

  6. Life history diversity in Klamath River steelhead

    USGS Publications Warehouse

    Hodge, Brian W.; Wilzbach, Peggy; Duffy, Walter G. G.; Quinones, Rebecca M.; Hobbs, James A.

    2016-01-01

    Oncorhynchus mykiss exhibits a vast array of life histories, which increases its likelihood of persistence by spreading risk of extirpation among different pathways. The Klamath River basin (California–Oregon) provides a particularly interesting backdrop for the study of life history diversity in O. mykiss, in part because the river is slated for a historic and potentially influential dam removal and habitat recolonization project. We used scale and otolith strontium isotope (87Sr/86Sr) analyses to characterize life history diversity in wildO. mykiss from the lower Klamath River basin. We also determined maternal origin (anadromous or nonanadromous) and migratory history (anadromous or nonanadromous) of O. mykiss and compared length and fecundity at age between anadromous (steelhead) and nonanadromous (Rainbow Trout) phenotypes of O. mykiss. We identified a total of 38 life history categories at maturity, which differed in duration of freshwater and ocean rearing, age at maturation, and incidence of repeat spawning. Approximately 10% of adult fish sampled were nonanadromous. Rainbow Trout generally grew faster in freshwater than juvenile steelhead; however, ocean growth afforded adult steelhead greater length and fecundity than adult Rainbow Trout. Although 75% of individuals followed the migratory path of their mother, steelhead produced nonanadromous progeny and Rainbow Trout produced anadromous progeny. Overall, we observed a highly diverse array of life histories among Klamath River O. mykiss. While this diversity should increase population resilience, recent declines in the abundance of Klamath River steelhead suggest that life history diversity alone is not sufficient to stabilize a population. Our finding that steelhead and Rainbow Trout give rise to progeny of the alternate form (1) suggests that dam removal might lead to a facultatively anadromous O. mykiss population in the upper basin and (2) raises the question of whether both forms of

  7. Prevention and treatment of Nitrite toxicity in juvenile steelhead trout (Salmo gairdneri)

    USGS Publications Warehouse

    Wedemeyer, Gary A.; Yasutake, W.T.

    1978-01-01

    The efficacy of mineral salts, pH, and tetramethylthianine (methylene blue) treatment in reducing the acute toxicity of nitrite to fingerling steelhead trout (Salmo gairdneri) was determined using a static bioassay system at 10 °C. The acute toxicity (96-h LC50) was reduced by a factor of about 24 for 5-g steelhead and 13 for 10-g fish when the total water hardness was increased from 25 to 300 mg/L (as CaCO3). NaCl or CaCl2 additions (0–200 mg/L) reduced toxicity by a factor of up to 3 for NaCl and 50 for CaCl2. Increasing the pH from 6.0 to 8.0 decreased toxicity by a factor of about 8 for the smaller and 3 for the larger fish. Methylene blue at 0.1 or 1.0 mg/L was effective in decreasing acute toxicity. For alleviating methemoglobinemia, removing the fish to freshwater for 48 h was about as effective as 1.0 mg/L methylene blue. Chronic exposure in soft water to 0.03 mg/L NO2-N for 6 mo caused no significant growth reduction, gill histological changes, hematological dyscrasias, or impaired ability of the smolts to adapt to 30‰ seawater and grow for an additional 2 mo. Key words: nitrite, toxicity, fish, methylene blue, pH, salts, acute toxicity, chronic toxicity

  8. EFFECTS OF AIR-SUPERSATURATED WATER ON SURVIVAL OF PACIFIC SALMON AND STEELHEAD SMOLTS

    EPA Science Inventory

    Coho (Oncorhynchus kisutch) and sockeye (O. nerka) salmon smolts and steelhead trout (Salmo gairdneri) smolts were exposed to several concentrations of air-supersaturated water in the laboratory from March through June, 1974, the normal fish migration period in the Columbia River...

  9. Population Structure of Columbia River Basin Chinook Salmon and Steelhead Trout, Technical Report 2001.

    SciTech Connect

    Brannon, E.L.; National Science Foundation

    2002-08-01

    The population structure of chinook salmon and steelhead trout is presented as an assimilation of the life history forms that have evolved in synchrony with diverse and complex environments over their Pacific range. As poikilotherms, temperature is described as the overwhelming environmental influence that determines what life history options occur and where they are distributed. The different populations represent ecological types referred to as spring-, summer-, fall, and winter-run segments, as well as stream- and ocean-type, or stream- and ocean-maturing life history forms. However, they are more correctly described as a continuum of forms that fall along a temporal cline related to incubation and rearing temperatures that determine spawn timing and juvenile residence patterns. Once new habitats are colonized, members of the founding populations spread through adaptive evolution to assume complementary life history strategies. The related population units are collectively referred to as a metapopulation, and members most closely associated within common temporal and geographic boundaries are designated as first-order metapopulations. Population structure of chinook salmon and steelhead in the Columbia Basin, therefore, is the reflection of the genetic composition of the founding source or sources within the respective region, shaped by the environment, principally temperature, that defines life history evolutionary strategy to maximize fitness under the conditions delineated. The complexity of structure rests with the diversity of opportunities over the elevations that exist within the Basin. Consistent with natural selection, rather than simply attempting to preserve populations, the challenge is to provide opportunities to expand their range to new or restored habitat that can accommodate genetic adaptation as directional environmental changes are elaborated. Artificial propagation can have a critical role in this process, and the emphasis must be placed on

  10. Experimental evaluation of rainbow trout Oncorhynchus mykiss predation on longnose dace Rhinichthys cataractae

    USGS Publications Warehouse

    Turek, Kelly C.; Pegg, Mark A.; Pope, Kevin L.

    2014-01-01

    Laboratory and in-stream enclosure experiments were used to determine whether rainbow trout Oncorhynchus mykiss influence survival of longnose dace Rhinichthys cataractae. In the laboratory, adult rainbow trout preyed on longnose dace in 42% of trials and juvenile rainbow trout did not prey on longnose dace during the first 6 h after rainbow trout introduction. Survival of longnose dace did not differ in the presence of adult rainbow trout previously exposed to active prey and those not previously exposed to active prey ( = 0.28, P = 0.60). In field enclosures, the number of longnose dace decreased at a faster rate in the presence of rainbow trout relative to controls within the first 72 h, but did not differ between moderate and high densities of rainbow trout (F2,258.9 = 3.73, P = 0.03). Additionally, longnose dace were found in 7% of rainbow trout stomachs after 72 h in enclosures. Rainbow trout acclimated to the stream for longer periods had a greater initial influence on the number of longnose dace remaining in enclosures relative to those acclimated for shorter periods regardless of rainbow trout density treatment (F4,148.5 = 2.50, P = 0.04). More research is needed to determine how predation rates will change in natural environments, under differing amounts of habitat and food resources and in the context of whole assemblages. However, if rainbow trout are introduced into the habitat of longnose dace, some predation on longnose dace is expected, even when rainbow trout have no previous experience with active prey.

  11. How much does inbreeding contribute to the reduced fitness of hatchery-born steelhead (Oncorhynchus mykiss) in the wild?

    PubMed

    Christie, Mark R; French, Rod A; Marine, Melanie L; Blouin, Michael S

    2014-01-01

    Many declining populations are supplemented with captive-born individuals that are released directly into the wild. Because captive-born individuals can have lower fitness in the wild than their wild-born counterparts, a comprehensive understanding of the mechanisms responsible for the reduced fitness of these individuals is required for appropriate conservation and management decisions. Inbreeding among captive-born individuals is one plausible mechanism because captive breeding programs frequently use small numbers of breeders to create large numbers of siblings that are subsequently released together into the wild. We tested this hypothesis in a supplementation program for steelhead (Oncorhynchus mykiss) from the Hood River, Oregon, for which first-generation hatchery fish were demonstrated to have lower fitness in the wild than their wild-born counterparts. To determine the contribution of inbreeding to this fitness decline, we first assigned 11 run-years of hatchery steelhead (3005 fish) back to their broodstock parents (462 fish) using 8 polymorphic microsatellite loci. By combining pedigree analyses with species-specific estimates of genetic load, we found that inbreeding could at most account for a 1-4% reduction in the fitness of hatchery fish relative to wild fish. Thus, inbreeding alone cannot adequately explain the 15% average fitness decline observed in first-generation hatchery fish from this population. PMID:24187426

  12. The evolutionary history of steelhead (Oncorhynchus mykiss) along the US Pacific Coast: Developing a conservation strategy using genetic diversity

    USGS Publications Warehouse

    Nielsen, J.L.

    1999-01-01

    Changes in genetic variation across a species range may indicate patterns of population structure resulting from past ecological and demographic events that are otherwise difficult to infer and thus provide insight into evolutionary development. Genetic data is used, drawn from 11 microsatellite loci amplified from anadromous steelhead (Oncorhynchus mykiss) sampled throughout its range in the eastern Pacific Ocean, to explore population structure at the southern edge in California. Steelhead populations in this region represent less than 10% of their reported historic abundance and survive in very small populations found in fragmented habitats. Genetic data derived from three independent molecular systems (allozymes, mtDNA, and microsatellites) have shown that the southernmost populations are characterized by a relatively high genetic diversity. Two hypothetical models supporting genetic population substructure such as observed were considered: (1) range expansion with founder-flush effects and subsequent population decline; (2) a second Pleistocene radiation from the Gulf of California. Using genetic and climatic data, a second Pleistocene refugium contributing to a southern ecotone seems more feasible. These data support strong conservation measures based on genetic diversity be developed to ensure the survival of this uniquely diverse gene pool.

  13. Differential susceptibility in steelhead trout populations to an emergent MD strain of infectious hematopoietic necrosis virus

    USGS Publications Warehouse

    Breyta, R.; Jones, Amelia; Kurath, Gael

    2014-01-01

    A significant emergence of trout-adapted MD subgroup infectious hematopoietic necrosis virus (IHNV) began in the coastal region of Washington State, USA, in 2007. This emergence event lasted until 2011 and caused both asymptomatic adult fish infection and symptomatic epidemic disease and mortality in juvenile fish. Incidence of virus during this emergence demonstrated a heterogeneous distribution among rivers of the coastal region, leaving fish populations of some rivers apparently untouched while others suffered significant and recurrent infection and mortality (Breyta et. al. 2013; Dis Aquat Org 104:179-195). In this study, we examined the possible contribution of variations in susceptibility of fish populations, age-related resistance, and virus virulence to the observed landscape heterogeneity. We found that the most significant variable was host susceptibility: by controlled experimental challenge studies steelhead trout populations with no history of IHNV infection were 1 to 3 orders of magnitude more sensitive than a fish population with a long history of IHNV infection. In addition, 2 fish populations from the same river, which descended relatively recently from a common ancestral population, demonstrated 1 to 2 orders of magnitude difference in susceptibility. Fish age-related development of resistance was most evident in the more susceptible of 2 related fish populations. Finally, the strain of virus involved in the 2007 coastal Washington emergence had high virulence but was within the range of other known M group viruses tested. These results suggest that one major driver of landscape heterogeneity in the 2007 coastal Washington IHNV emergence was variation in fish population susceptibility and that this trait may have a heritable component.

  14. Differential susceptibility in steelhead trout populations to an emergent MD strain of infectious hematopoietic necrosis virus.

    PubMed

    Breyta, Rachel; Jones, Amelia; Kurath, Gael

    2014-11-13

    A significant emergence of trout-adapted MD subgroup infectious hematopoietic necrosis virus (IHNV) began in the coastal region of Washington State, USA, in 2007. This emergence event lasted until 2011 and caused both asymptomatic adult fish infection and symptomatic epidemic disease and mortality in juvenile fish. Incidence of virus during this emergence demonstrated a heterogeneous distribution among rivers of the coastal region, leaving fish populations of some rivers apparently untouched while others suffered significant and recurrent infection and mortality (Breyta et. al. 2013; Dis Aquat Org 104:179-195). In this study, we examined the possible contribution of variations in susceptibility of fish populations, age-related resistance, and virus virulence to the observed landscape heterogeneity. We found that the most significant variable was host susceptibility: by controlled experimental challenge studies steelhead trout populations with no history of IHNV infection were 1 to 3 orders of magnitude more sensitive than a fish population with a long history of IHNV infection. In addition, 2 fish populations from the same river, which descended relatively recently from a common ancestral population, demonstrated 1 to 2 orders of magnitude difference in susceptibility. Fish age-related development of resistance was most evident in the more susceptible of 2 related fish populations. Finally, the strain of virus involved in the 2007 coastal Washington emergence had high virulence but was within the range of other known M group viruses tested. These results suggest that one major driver of landscape heterogeneity in the 2007 coastal Washington IHNV emergence was variation in fish population susceptibility and that this trait may have a heritable component. PMID:25392039

  15. Ontogenetic taurine biosynthesis ability in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Wang, Xuan; He, Gen; Mai, Kangsen; Xu, Wei; Zhou, Huihui

    2015-07-01

    Taurine (2-aminoethane sulfonic acid) plays important roles in multiple physiological processes including osmoregulation, bile salt conjugation and membrane protection. It is known that taurine biosynthesis varies in different fish species. However, its ontogenetic regulation has not been clear. In the present study, we found that the hepatic concentrations of taurine increased marginally with rainbow trout growth. The mRNA expression, protein levels and enzyme activities of key enzymes involved in taurine biosynthesis, cysteine dioxygenase (CDO) and cysteine sulfinate decarboxylase (CSD), were analyzed. Our results showed that the mRNA levels and protein abundances of CSD increased dramatically with the development of rainbow trout stages while the enzyme activities showed a slight improvement. However, the expression and activities of CDO decreased with rainbow trout growth. These results provide valuable information on defining the exact supplementation of taurine in diets for different stages of rainbow trout and give new insights into elucidating the regulation of taurine metabolism in rainbow trout. PMID:25773436

  16. Seasonal variation in habitat use of juvenile Steelhead in a tributary of Lake Ontario

    USGS Publications Warehouse

    Studdert, Emily W.; Johnson, James H.

    2015-01-01

    We examined seasonal-habitat use by subyearling and yearling Oncorhynchus mykiss (Rainbow Trout or Steelhead) in Trout Brook, a tributary of the Salmon River, NY. We determined daytime fish-habitat use and available habitat during August and October of the same year and observed differences in habitat selection among year classes. Water depth and cover played the greatest role in Steelhead habitat use. During summer and autumn, we found yearling Steelhead in areas with deeper water and more cover than where we observed subyearling Steelhead. Both year classes sought out areas with abundant cover during both seasons; this habitat was limited within the stream reach. Subyearling Steelhead were associated with more cover during autumn, even though available cover within the stream reach was greater during summer. Principal component analysis showed that variation in seasonal-habitat use was most pronounced for subyearling Steelhead and that yearling Steelhead were more selective in their habitat use than subyearling Steelhead. The results of this study contribute to a greater understanding of how this popular sportfish is adapting to a new environment and the factors that may limit juvenile Steelhead survival. Our findings provide valuable new insights into the seasonal-habitat requirements of subyearling and yearling Steelhead that can be used by fisheries managers to enhance and protect the species throughout the Great Lakes region.

  17. The ultrastructure of spontaneous coronary arterial lesions in steelhead trout (Salmo gairdneri).

    PubMed Central

    House, E. W.; Benditt, E. P.

    1981-01-01

    Electron-microscopic examination of spontaneously occurring coronary arterial lesions in adult spawning steelhead trout showed them to be subendothelial accumulations of modified smooth muscle cells covered by an intact endothelium. Some of the cells in the nodules appeared highly vacuolated and seemed to be associated with varying amounts of collagen and elastin. The internal elastic lamina was often doubled with smooth muscle cells between the layers. The thickness of the internal elastica was altered and, in some lesions, penetrated by smooth muscle cells. In the smallest lesions, smooth muscle cells appeared to be penetrating the internal elastic lamina and were usually close to a highly vacuolated intimal endothelial cell. The underlying medial layer frequently exhibited altered orientation of the cells, with the frequent appearance of increased collagen and amorphous extracellular material. No lipid was present in any lesion. Although vacuolation of endothelial cells suggested some alteration in endothelial cells, at least in developed lesions, no evidence of endothelial denudation over lesions was observed. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 PMID:7294154

  18. Effects of frying in various cooking oils on fatty acid content of farmed rainbow trout (Oncorhynchus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our goal was to describe the effects of frying with various oils on the fatty acid content of rainbow trout. Four different oils were evaluated (peanut oil, high oleic sunflower oil, corn oil, and canola oil). Farmed rainbow trout (Oncorhynchus mykiss) fillets were sliced into three portions and eac...

  19. Effects of triploidy on growth and protein degradation during the recovery from feed deprivation in rainbow trout (Oncorhynchus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identifying physiological differences between diploid and triploid rainbow trout will help define how ploidy affects mechanisms that impact growth and nutrient utilization. In this study juvenile diploid and triploid female rainbow trout (Oncorhynchus mykiss) were either continually fed or fasted f...

  20. Identification of Estrogen-responsive Vitelline Envelope Protein Fragments from Rainbow Trout (Oncorhynchus mykiss) Plasma Using Mass Spectrometry

    EPA Science Inventory

    Plasma protein biomarkers associated with exposure of rainbow trout (Oncorhynchus mykiss) to 17β-estradiol were isolated and identified using novel sample preparation techniques and state-of-the-art mass spectrometry and bioinformatics approaches. Juvenile male and female trout ...

  1. Histopathological findings in farmed rainbow trout (Oncorhynchus mykiss) naturally infected with 3 different Aeromonas species.

    PubMed

    Zepeda-Velázquez, Andrea Paloma; Vega-Sánchez, Vicente; Salgado-Miranda, Celene; Soriano-Vargas, Edgardo

    2015-07-01

    This study describes the macroscopic and microscopic lesions in farmed rainbow trout (Oncorhynchus mykiss) naturally infected with genetically identified Aeromonas salmonicida, A. hydrophila, and A. veronii species. The genus Aeromonas includes bacteria that naturally inhabit both waterways and organisms. At least 27 Aeromonas species have been identified to date, some of which can cause significant economic losses in aquaculture. As up to 68.8% of Aeromonas isolates may be misidentified in routine biochemical and phenotypic tests, however, reported cases of Aeromonas infection in fish may be wrongly identified. Our findings confirmed that the 3 Aeromonas species studied are associated with septicemia and dermal lesions in rainbow trout. PMID:26130859

  2. Histopathological findings in farmed rainbow trout (Oncorhynchus mykiss) naturally infected with 3 different Aeromonas species

    PubMed Central

    Zepeda-Velázquez, Andrea Paloma; Vega-Sánchez, Vicente; Salgado-Miranda, Celene; Soriano-Vargas, Edgardo

    2015-01-01

    This study describes the macroscopic and microscopic lesions in farmed rainbow trout (Oncorhynchus mykiss) naturally infected with genetically identified Aeromonas salmonicida, A. hydrophila, and A. veronii species. The genus Aeromonas includes bacteria that naturally inhabit both waterways and organisms. At least 27 Aeromonas species have been identified to date, some of which can cause significant economic losses in aquaculture. As up to 68.8% of Aeromonas isolates may be misidentified in routine biochemical and phenotypic tests, however, reported cases of Aeromonas infection in fish may be wrongly identified. Our findings confirmed that the 3 Aeromonas species studied are associated with septicemia and dermal lesions in rainbow trout. PMID:26130859

  3. Recombinant interleukin-1β dilates steelhead trout coronary microvessels: effect of temperature and role of the endothelium, nitric oxide and prostaglandins

    PubMed Central

    Costa, Isabel A. S. F.; Hein, Travis W.; Secombes, Christopher J.; Gamperl, A. Kurt

    2015-01-01

    ABSTRACT Interleukin (IL)-1β is associated with hypotension and cardiovascular collapse in mammals during heat stroke, and the mRNA expression of this pro-inflammatory cytokine increases dramatically in the blood of Atlantic cod (Gadus morhua) at high temperatures. These data suggest that release of IL-1β at high temperatures negatively impacts fish cardiovascular function and could be a primary determinant of upper thermal tolerance in this taxa. Thus, we measured the concentration-dependent response of isolated steelhead trout (Oncorhynchus mykiss) coronary microvessels (<150 μm in diameter) to recombinant (r) IL-1β at two temperatures (10 and 20°C). Recombinant IL-1β induced a concentration-dependent vasodilation with vessel diameter increasing by approximately 8 and 30% at 10−8 and 10−7 mol l−1, respectively. However, this effect was not temperature dependent. Both vessel denudation and cyclooxygenase blockade (by indomethacin), but not the nitric oxide (NO) antagonist L-NIO, inhibited the vasodilator effect of rIL-1β. In contrast, the concentration-dependent dilation caused by the endothelium-dependent calcium ionophore A23187 was completely abolished by L-NIO and indomethacin, suggesting that both NO and prostaglandin signaling mechanisms exist in the trout coronary microvasculature. These data: (1) are the first to demonstrate a functional link between the immune and cardiovascular systems in fishes; (2) suggest that IL-1β release at high temperatures may reduce systemic vascular resistance, and thus, the capacity of fish to maintain blood pressure; and (3) provide evidence that both NO and prostaglandins play a role in regulating coronary vascular tone, and thus, blood flow. PMID:26026045

  4. The influence of social status on hepatic glucose metabolism in rainbow trout Oncorhynchus mykiss.

    PubMed

    Gilmour, Kathleen M; Kirkpatrick, Sheryn; Massarsky, Andrey; Pearce, Brenda; Saliba, Sarah; Stephany, Céleste-Élise; Moon, Thomas W

    2012-01-01

    The effects of chronic social stress on hepatic glycogen metabolism were examined in rainbow trout Oncorhynchus mykiss by comparing hepatocyte glucose production, liver glycogen phosphorylase (GP) activity, and liver β-adrenergic receptors in dominant, subordinate, control, fasted, and cortisol-treated fish. Hepatocyte glucose production in subordinate fish was approximately half that of dominant fish, reflecting hepatocyte glycogen stores in subordinate trout that were just 16% of those in dominant fish. Fasting and/or chronic elevation of cortisol likely contributed to these differences based on similarities among subordinate, fasted, and cortisol-treated fish. However, calculation of the "glycogen gap"--the difference between glycogen stores used and glucose produced--suggested an enhanced gluconeogenic potential in subordinate fish that was not present in fasted or cortisol-treated trout. Subordinate, fasted, and cortisol-treated trout also exhibited similar GP activities (both total activity and that of the active or a form), and these activities were in all cases significantly lower than those in control trout, perhaps reflecting an attempt to protect liver glycogen stores or a modified capacity to activate GP. Dominant trout exhibited the lowest GP activities (20%-24% of the values in control trout). Low GP activities, presumably in conjunction with incoming energy from feeding, allowed dominant fish to achieve the highest liver glycogen concentrations (double the value in control trout). Liver membrane β-adrenoceptor numbers (assessed as the number of (3)H-CGP binding sites) were significantly lower in subordinate than in dominant trout, although this difference did not translate into attenuated adrenergic responsiveness in hepatocyte glucose production in vitro. Transcriptional regulation, likely as a result of fasting, was indicated by significantly lower β(2)-adrenoceptor relative mRNA levels in subordinate and fasted trout. Collectively, the data

  5. Life-history organization of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) in Yellowstone Lake

    USGS Publications Warehouse

    Gresswell, Robert E.; Liss, W.J.; Larson, Gary L.

    1994-01-01

    Life-history organization of the cutthroat trout (Oncorhynchus clarki) may be viewed at various levels, including species, subspecies, metapopulation, population, or individual. Each level varies in spatial scale and temporal persistence, and components at each level continually change with changes in environment. Cutthroat trout are widely distributed throughout the western United States, occurring in such diverse environments as coastal rivers of the Pacific Northwest and interior streams of the Great Basin. During its evolution the species has organized into 14 subspecies with many different life-history characteristics and habitat requirements. Within subspecies, organization is equally complex. For example, life-history traits, such as average size and age, migration strategy, and migration timing, vary among individual spawning populations of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) in tributary streams of Yellowstone Lake. Understanding the effects of human perturbations on life-history organization is critical for management of the cutthroat trout and other polytypic salmonid species. Loss of diversity at any hierarchical level jeopardizes the long-term ability of the species to adapt to changing environments, and it may also lead to increased fluctuations in abundance and yield and increase the risk of extinction.

  6. Dietary effects of Spirulina platensis on hematological and serum biochemical parameters of rainbow trout (Oncorhynchus mykiss).

    PubMed

    Yeganeh, Sakineh; Teimouri, Mahdi; Amirkolaie, Abdolsamad Keramat

    2015-08-01

    This study evaluated the effects of diets containing 0, 2.5, 5, 7.5 and 10% of Spirulina platensis on hematological and serum biochemical parameters of rainbow trout (Oncorhynchus mykiss). Fish (n=180; 101±8 g) were randomly divided into fifteen 300 L fiberglass tanks in triplicates for a period of ten weeks. The RBC, WBC, hemoglobin, total protein and albumin levels increased significantly in the groups supplemented with S. platensis. Dietary inclusion of S. platensis had no significant effects on hematocrit, cholesterol, triglyceride and lactate of the blood. HDL-cholesterol was larger in rainbow trout fed 10% S. platensis in comparison with the other diets, whereas LDL-cholesterol significantly decreased with increasing of S. platensis inclusion. Cortisol and glucose significantly decreased with increasing of S. platensis inclusion. The present results demonstrate that inclusion of 10% S. platensis can be introduced as an immunostimulant in rainbow trout diets. PMID:26267095

  7. Efficacy of selected oral chemotherapeutants against Ichthyophthirius multifiliis (Ciliophora: Ophyroglenidae) infecting rainbow trout Oncorhynchus mykiss.

    PubMed

    Shinn, Andrew P; Wootten, Rodney; Côté, Isabelle; Sommerville, Christina

    2003-06-20

    The chemotherapeutic efficacy of 6 in-feed compounds against Ichthyophthirius multifiliis Fouquet, 1876 was assessed using experimental infections of rainbow trout Oncorhynchus mykiss (Walbaum) fingerlings. Trial doses of 104 ppm amprolium hydrochloride or 65 ppm clopidol fed to fish for 10 d prior to infection significantly reduced the number of trophonts establishing in trout fingerlings by 62.0 and 35.2% respectively. In-feed treatments of infected trout with either 63 or 75 ppm amprolium hydrochloride, 92 ppm clopidol, or 38, 43 or 47 ppm salinomycin sodium for 10 d also significantly reduced the number of surviving trophonts by 77.6 and 32.2% for amprolium, 20.1% for clopidol and 80.2, 71.9 and 93.3% respectively for salinomycin sodium. PMID:12887250

  8. Use of behavioral responses of rainbow trout Oncorhynchus mykiss in identifying sublethal exposure to hexavalent chromium.

    PubMed

    Svecevicius, Gintaras

    2009-05-01

    Laboratory tests were conducted in a flow-through apparatus on 1-year-old rainbow trout Oncorhynchus mykiss to evaluate the sensitivity of a number of their behavioral responses to hexavalent chromium (Cr(6+)). Test fish were exposed to Cr(6+) concentrations corresponding to 0.001-1 parts of the rainbow trout 96-h LC50 (0.029-28.5 mg Cr/L, respectively) in short-term (15 min) tests. Sensitivity parameter responses could be arranged into the following sequence: latent period of detection response = locomotor activity > gill ventilation frequency > coughing rate. All the rainbow trout responses were sensitive behavioral indicators of sublethal exposure. Behavioral responses meet the criteria as rapid tools for bioassay testing and could be easily standardized using Cr(6+) as a reference toxicant. PMID:19190838

  9. Whole body and tissue blood volumes of two strains of rainbow trout (Oncorhynchus mykiss )

    USGS Publications Warehouse

    Gingerich, W.H.; Pityer, R.A.; Rach, J.J.

    1990-01-01

    1. Estimates of apparent packed cell, plasma and total blood volumes for the whole body and for 13 selected tissues were compared between Kamloops and Wytheville strains of rainbow trout (Oncorhynchus mykiss) by the simultaneous injection of two vascular tracers, radiolabeled trout erythrocytes (51Cr-RBC) and radioiodated bovine serum albumin (125I-BSA). 2. Whole body total blood volume, plasma volume and packed cell volume were slightly, but not significantly greater in the Wytheville trout, whereas, the apparent plasma volumes and total blood volumes in 4 of 13 tissues were significantly greater in the Kamloops strain. 3. Differences were most pronounced in highly perfused organs, such as the liver and kidney and in organs of digestion such as the stomach and intestines. 4. Differences in blood volumes between the two strains may be related to the greater permeability of the vascular membranes in the Kamloops strain fish.

  10. Staphylococcus warneri, a resident skin commensal of rainbow trout (Oncorhynchus mykiss) with pathobiont characteristics

    PubMed Central

    Rami, Musharrafieh; Luca, Tacchi; Joshua, Trujeque; Scott, LaPatra; Irene, Salinas

    2014-01-01

    Commensal microorganisms live in association with the mucosal surfaces of all vertebrates. The skin of teleost fish is known to harbor commensals. In this study we report for the first time the presence of an intracellular Gram positive bacteria, Staphylococcus warneri that resides in the skin epidermis of rainbow trout (Oncorhynchus mykiss). S. warneri was isolated from healthy hatchery trout skin epithelial cells. In situ hybridization confirmed the intracellular nature of the bacterium. Skin explants exposed in vitro to S. warneri or the extracellular pathogen Vibrio anguillarum show that S. warneri is able to induce an anti-inflammatory cytokine status via TGF-β 1b compared to the pro-inflammatory responses (IL-1β , IL-6 and TNF-α) elicited by V. anguillarum. In vivo experiments showed that S. warneri is not pathogenic to rainbow trout when injected intraperitoneally at high concentrations. However, S. warneri is able to stimulate V. anguillarum growth and biofilm formation on rainbow trout scales. Our results demonstrate that rainbow trout skin commensals such as S. warneri have the potential to become indirect pathobionts by enhancing growth and biofilm formation of pathogens such as V. anguillarum. These results show that fish farming practices (i.e. handling and other manipulations) can alter the skin microbiota and compromise the skin health of rainbow trout. PMID:24438987

  11. Staphylococcus warneri, a resident skin commensal of rainbow trout (Oncorhynchus mykiss) with pathobiont characteristics.

    PubMed

    Musharrafieh, Rami; Tacchi, Luca; Trujeque, Joshua; LaPatra, Scott; Salinas, Irene

    2014-02-21

    Commensal microorganisms live in association with the mucosal surfaces of all vertebrates. The skin of teleost fish is known to harbor commensals. In this study we report for the first time the presence of an intracellular Gram positive bacteria, Staphylococcus warneri that resides in the skin epidermis of rainbow trout (Oncorhynchus mykiss). S. warneri was isolated from healthy hatchery trout skin epithelial cells. In situ hybridization confirmed the intracellular nature of the bacterium. Skin explants exposed in vitro to S. warneri or the extracellular pathogen Vibrio anguillarum show that S. warneri is able to induce an anti-inflammatory cytokine status via TGF-β1b compared to the pro-inflammatory responses (IL-1β, IL-6 and TNF-∝) elicited by V. anguillarum. In vivo experiments showed that S. warneri is not pathogenic to rainbow trout when injected intraperitoneally at high concentrations. However, S. warneri is able to stimulate V. anguillarum growth and biofilm formation on rainbow trout scales. Our results demonstrate that rainbow trout skin commensals such as S. warneri have the potential to become indirect pathobionts by enhancing growth and biofilm formation of pathogens such as V. anguillarum. These results show that fish farming practices (i.e. handling and other manipulations) can alter the skin microbiota and compromise the skin health of rainbow trout. PMID:24438987

  12. Sex biased survival and differences in migration of wild steelhead (Oncorhynchus mykiss) smolts from two coastal Oregon rivers

    USGS Publications Warehouse

    Thompson, Neil F.; Leblanc, Camille A.; Romer, Jeremy D.; Schreck, Carl B.; Blouin, Michael S.; Noakes, David L. G.

    2016-01-01

    In salmonids with partial migration, females are more likely than males to undergo smoltification and migrate to the ocean (vs. maturing in freshwater). However, it is not known whether sex affects survivorship during smolt migration (from fresh water to entry into the ocean). We captured wild steelhead (Oncorhynchus mykiss) smolts in two coastal Oregon rivers (USA) and collected fin tissue samples for genetic sex determination (2009; N = 70 in the Alsea and N = 69 in the Nehalem, 2010; N = 25 in the Alsea). We implanted acoustic tags and monitored downstream migration and survival until entry in to the Pacific Ocean. Survival was defined as detection at an estuary/ocean transition array. We found no effect of sex on smolt survivorship in the Nehalem River in 2009, or in the Alsea River in 2010. However, males exhibited significantly lower survival than females in the Alsea River during 2009. Residency did not influence this result as an equal proportion of males and females did not reach the estuary entrance (11% of males, 9% of females). The sexes did not differ in timing or duration of migration, so those variables seem unlikely to explain sex-biased survivorship. Larger males had higher odds of survival than smaller males in 2009, but the body size of females did not affect survivorship. The difference in survivorship between years in the Alsea River could be due to flow conditions, which were higher in 2010 than in 2009. Our findings suggest that sex may affect steelhead smolt survival during migration, but that the difference in survivorship may be weak and not a strong factor influencing adult sex ratios.

  13. Aggression and feeding of hatchery-reared and naturally reared steelhead (Oncorhynchus mykiss) fry in a laboratory flume and a comparison with observations in natural streams

    USGS Publications Warehouse

    Riley, S.C.; Tatara, C.P.; Scheurer, J.A.

    2005-01-01

    We quantified the aggression and feeding of naturally reared steelhead (Oncorhynchus mykiss) fry stocked into a laboratory flume with naturally reared fry or hatchery-reared fry from conventional and enriched rearing environments at three densities in the presence and absence of predators, and compared the aggression and feeding observed in the flume to that observed in two streams. Steelhead fry attack rate increased with density and was reduced in the presence of predators, but was not affected by rearing treatment. Threat rate appeared to increase with density and was significantly affected by rearing treatment combination, but was not significantly affected by predator presence. Feeding rate was not affected by density or rearing treatment, but was reduced in the presence of predators. The rate of aggression by steelhead fry in two streams was lower than that observed in the laboratory and did not increase with density. Rates of aggression and feeding of hatchery-reared and wild steelhead fry were not significantly different in the streams. Overall, we found no evidence that hatchery rearing environments caused higher aggression in steelhead fry. Laboratory observations of salmonid aggression, particularly at high density, may not reflect aggression levels in the wild. ?? 2005 NRC.

  14. A second generation genetic map for rainbow trout (Oncorhynchus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background Genetic maps characterizing the inheritance patterns of traits and markers have been developed for a wide range of species and used to study questions in biomedicine, agriculture, ecology and evolutionary biology. The status of rainbow trout genetic maps has progressed significantly over...

  15. Social stress modulates the cortisol response to an acute stressor in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Jeffrey, J D; Gollock, M J; Gilmour, K M

    2014-01-15

    In rainbow trout (Oncorhynchus mykiss) of subordinate social status, circulating cortisol concentrations were elevated under resting conditions but the plasma cortisol and glucose responses to an acute stressor (confinement in a net) were attenuated relative to those of dominant trout. An in vitro head kidney preparation, and analysis of the expression of key genes in the stress axis prior to and following confinement in a net were then used to examine the mechanisms underlying suppression of the acute cortisol stress response in trout experiencing chronic social stress. With porcine adrenocorticotropic hormone (ACTH) as the secretagogue, ACTH-stimulated cortisol production was significantly lower for head kidney preparations from subordinate trout than for those from dominant trout. Dominant and subordinate fish did not, however, differ in the relative mRNA abundance of melanocortin-2 receptor (MC2R), steroidogenic acute regulatory protein (StAR) or cytochrome P450 side chain cleavage enzyme (P450scc) within the head kidney, although the relative mRNA abundance of these genes was significantly higher in both dominant and subordinate fish than in sham trout (trout that did not experience social interactions but were otherwise treated identically to the dominant and subordinate fish). The relative mRNA abundance of all three genes was significantly higher in trout exposed to an acute net stressor than under control conditions. Upstream of cortisol production in the stress axis, plasma ACTH concentrations were not affected by social stress, nor was the relative mRNA abundance of the binding protein for corticotropin releasing factor (CRF-BP). The relative mRNA abundance of CRF in the pre-optic area of subordinate fish was significantly higher than that of dominant or sham fish 1h after exposure to the stressor. Collectively, the results indicate that chronic social stress modulates cortisol production at the level of the interrenal cells, resulting in an attenuated

  16. Relative contributions of neutral and non-neutral genetic differentiation to inform conservation of steelhead trout across highly variable landscapes.

    PubMed

    Matala, Andrew P; Ackerman, Michael W; Campbell, Matthew R; Narum, Shawn R

    2014-06-01

    Mounting evidence of climatic effects on riverine environments and adaptive responses of fishes have elicited growing conservation concerns. Measures to rectify population declines include assessment of local extinction risk, population ecology, viability, and genetic differentiation. While conservation planning has been largely informed by neutral genetic structure, there has been a dearth of critical information regarding the role of non-neutral or functional genetic variation. We evaluated genetic variation among steelhead trout of the Columbia River Basin, which supports diverse populations distributed among dynamic landscapes. We categorized 188 SNP loci as either putatively neutral or candidates for divergent selection (non-neutral) using a multitest association approach. Neutral variation distinguished lineages and defined broad-scale population structure consistent with previous studies, but fine-scale resolution was also detected at levels not previously observed. Within distinct coastal and inland lineages, we identified nine and 22 candidate loci commonly associated with precipitation or temperature variables and putatively under divergent selection. Observed patterns of non-neutral variation suggest overall climate is likely to shape local adaptation (e.g., potential rapid evolution) of steelhead trout in the Columbia River region. Broad geographic patterns of neutral and non-neutral variation demonstrated here can be used to accommodate priorities for regional management and inform long-term conservation of this species. PMID:25067950

  17. Relative contributions of neutral and non-neutral genetic differentiation to inform conservation of steelhead trout across highly variable landscapes

    PubMed Central

    Matala, Andrew P; Ackerman, Michael W; Campbell, Matthew R; Narum, Shawn R

    2014-01-01

    Mounting evidence of climatic effects on riverine environments and adaptive responses of fishes have elicited growing conservation concerns. Measures to rectify population declines include assessment of local extinction risk, population ecology, viability, and genetic differentiation. While conservation planning has been largely informed by neutral genetic structure, there has been a dearth of critical information regarding the role of non-neutral or functional genetic variation. We evaluated genetic variation among steelhead trout of the Columbia River Basin, which supports diverse populations distributed among dynamic landscapes. We categorized 188 SNP loci as either putatively neutral or candidates for divergent selection (non-neutral) using a multitest association approach. Neutral variation distinguished lineages and defined broad-scale population structure consistent with previous studies, but fine-scale resolution was also detected at levels not previously observed. Within distinct coastal and inland lineages, we identified nine and 22 candidate loci commonly associated with precipitation or temperature variables and putatively under divergent selection. Observed patterns of non-neutral variation suggest overall climate is likely to shape local adaptation (e.g., potential rapid evolution) of steelhead trout in the Columbia River region. Broad geographic patterns of neutral and non-neutral variation demonstrated here can be used to accommodate priorities for regional management and inform long-term conservation of this species. PMID:25067950

  18. Susceptibility of sexually mature rainbow trout, Oncorhynchus mykiss to experimental cryptobiosis caused by Cryptobia salmositica.

    PubMed

    Currie, Jaime L M; Woo, Patrick T K

    2007-09-01

    Sexually mature rainbow trout, Oncorhynchus mykiss, were highly susceptible to cryptobiosis caused by Cryptobia salmositica. Spawning female trout were more susceptible (higher parasitaemia and mortality) than sexually mature males. Most infected female trout (seven of nine) with eggs died before or shortly after spawning; however, none of the nine infected sexually matured males or the uninfected fish died. There was no significant difference in the severity of the anaemia between infected male and female trout. All infected males developed exophthalmia, while this clinical sign was not seen in any of the infected females nor in uninfected trout. The addition of 17 beta-estradiol (at physiological level or higher) did not enhance in vitro multiplication of the Cryptobia; however, fresh plasma from sexually mature females or males when added to cultures significantly increased in vitro multiplication of the pathogen. In addition, plasma from sexually mature females were significantly better than those from males in promoting in vitro parasite multiplication. Parasite multiplication did not increase after plasma from sexually mature fish were heat inactivated. PMID:17582534

  19. Inhibition of fish pathogens by the microbiota from rainbow trout (Oncorhynchus mykiss, Walbaum) and rearing environment.

    PubMed

    Araújo, Carlos; Muñoz-Atienza, Estefanía; Nahuelquín, Yanina; Poeta, Patrícia; Igrejas, Gilberto; Hernández, Pablo E; Herranz, Carmen; Cintas, Luis M

    2015-04-01

    This work reports the isolation and taxonomic identification of the cultivable total microbiota (TM) and Lactic Acid Bacteria (LAB) from rainbow trout (Oncorhynchus mykiss, Walbaum) and rearing environment from selected stages of the life-cycle, and the evaluation of the LAB antimicrobial activity against the main fish pathogens. TM and LAB isolates were randomly selected and identified by 16S rRNA and/or superoxide dismutase gene sequencing. Although a great diversity in the TM was observed, Enterobacteriaceae and Aeromonadaceae were clearly prevalent, while the genus Lactococcus was the predominant LAB. From a total of 1620 randomly selected LAB, 1159 isolates (71.5%) showed antimicrobial activity. From these, 248 isolates (21.4%) selected for their activity against, at least, four fish pathogens, were taxonomically identified, being Lactococcus lactis the most common species (164 isolates, 66.1%). Interestingly, 88 isolates (35.5%), including 55 L. lactis isolates, exerted activity against four strains of the rainbow trout pathogen Lactococcus garvieae. Our results demonstrate that rainbow trout and rearing environment are potential sources for the isolation of LAB, mainly lactococci, active against L. garvieae and other fish pathogens. Moreover, this is the first study describing the cultivable TM and LAB from rainbow trout intestine and rearing environment along the fish life-cycle. The host-derived LAB active against fish pathogens comprise potential candidates as probiotics in rainbow trout farming as an alternative or complementary strategy to antibiotics and vaccines for disease prevention. PMID:25464142

  20. Intensive Evaluation and Monitoring of Chinook Salmon and Steelhead Trout Production, Crooked River and Upper Salmon River Sites, 1994 Annual Report.

    SciTech Connect

    Kiefer, Russell B.; Lockhart, Jerald N.

    1997-06-01

    The purpose of this intensive monitoring project is to determine the number of returning chinook and steelhead adults necessary to achieve optimal smolt production, and develop mitigation accounting based on increases in smolt production. Two locations in Idaho are being intensively studied to meet these objectives. Information from this research will be applied to parr monitoring streams statewide to develop escapement objectives and determine success of habitat enhancement projects. This project to date has developed good information on the relationship between adult chinook salmon escapement and smolt production at low to medium seeding levels. This information for steelhead includes a fair estimate of carrying capacity. To date, we have been unable to accurately estimate egg-to-parr survival for steelhead. Future efforts will include determining the relationship between adult steelhead trout escapement and age 1 + parr production, determining environmental and habitat factors that affect smolt production, and developing project results to help the region make good management decisions for anadromous fish.

  1. Microsomal biotransformation of chlorpyrifos, parathion and fenthion in rainbow trout (Oncorhynchus mykiss) and coho salmon (Oncorhynchus kisutch): mechanistic insights into interspecific differences in toxicity.

    PubMed

    Lavado, Ramon; Schlenk, Daniel

    2011-01-17

    Rainbow trout often serve as a surrogate species evaluating xenobiotic toxicity in cold-water species including other salmonids of the same genus, which are listed as threatened or endangered. Biotransformation tends to show species-specific patterns that influence susceptibility to xenobiotic toxicity, particularly organophosphate insecticides (OPs). To evaluate the contribution of biotransformation in the mechanism of toxicity of three organophosphate (phosphorothionate) insecticides, (chlorpyrifos, parathion and fenthion), microsomal bioactivation and detoxification pathways were measured in gills, liver and olfactory tissues in juvenile rainbow trout (Oncorhynchus mykiss) and compared to juvenile coho salmon (Oncorhynchus kisutch). Consistent with species differences in acute toxicity, significantly higher chlorpyrifos bioactivation was found in liver microsomes of rainbow trout (up to 2-fold) when compared with coho salmon. Although bioactivation to the oxon was observed, the catalytic efficiency towards chlorpyrifos dearylation (detoxification) was significantly higher in liver for both species (1.82 and 0.79 for trout and salmon, respectively) when compared to desulfuration (bioactivation). Bioactivation of parathion to paraoxon was significantly higher (up to 2.2-fold) than detoxification to p-nitrophenol in all tissues of both species with rates of conversion in rainbow trout, again significantly higher than coho salmon. Production of fenoxon and fenthion sulfoxides from fenthion was detected only in liver and gills of both species with activities in rainbow trout significantly higher than coho salmon. NADPH-dependent cleavage of fenthion was observed in all tissues, and was the only activity detected in olfactory tissues. These results indicate rainbow trout are more sensitive than coho salmon to the acute toxicity of OP pesticides because trout have higher catalytic rates of oxon formation. Thus, rainbow trout may serve as a conservative surrogate

  2. Ibuprofen metabolism in the liver and gill of rainbow trout, Oncorhynchus mykiss.

    PubMed

    Gomez, C F; Constantine, L; Moen, M; Vaz, A; Wang, W; Huggett, Duane B

    2011-03-01

    The presence of pharmaceuticals in the environment has become an important topic of discussion with respect to pharmaceutical absorption, metabolism and elimination in fish. This study investigates the metabolism of ibuprofen by rainbow trout (Oncorhynchus mykiss). In vitro metabolic loss of parent compound was measured in gill and liver S9 and microsomal fractions. Metabolite analysis found 2-hydroxy-ibuprofen as the major metabolite in uninduced S9 fractions. Supplementing S9 fractions with UDPGA did not significantly enhance metabolism. Additionally, assays involving the induction and inhibition of specific CYP isozymes support CYP1A2 as a possible metabolic pathway in fish. PMID:21301807

  3. TOXICITY OF FENVALERATE TO DEVELOPING STEELHEAD TROUT FOLLOWING CONTINUOUS OR INTERMITTENT EXPOSURE

    EPA Science Inventory

    Environmental toxicant exposures commonly vary in terms of duration and concentration. However, laboratory toxicity tests usually entail continuous exposures to constant concentrations. The authors compared survival, growth, and toxicant accumulation in early life-stage steelhead...

  4. Fast genomic biomarker responses of retene and pyrene in liver of juvenile rainbow trout, Oncorhynchus mykiss.

    PubMed

    Räsänen, Kati; Arsiola, Tiina; Oikari, Aimo

    2012-10-01

    We studied the transcriptive effects of two PAHs, retene (RET) and pyrene (PYR), in three equimolar sublethal concentrations (0.9-10 μg/L) in the liver of juvenile rainbow trout, Oncorhynchus mykiss. After 24 h of in vivo exposure, expressions of selected genes (CYP1A, Hsp30, Hsp70, Grp78, Sep15, GP1) were analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). These PAHs changed the studied gene transcriptions differently, but not significantly, except for CYP1A, which was induced only by RET. RET induced CYP1A gene expression even at low, environmentally realistic concentrations in the liver of juvenile rainbow trout. PMID:22864635

  5. Functional characterization of a BCL10 isoform in the rainbow trout Oncorhynchus mykiss

    PubMed Central

    Mazzone, Pellegrino; Scudiero, Ivan; Coccia, Elena; Ferravante, Angela; Paolucci, Marina; D’Andrea, Egildo Luca; Varricchio, Ettore; Pizzulo, Maddalena; Reale, Carla; Zotti, Tiziana; Vito, Pasquale; Stilo, Romania

    2015-01-01

    The complexes formed by BCL10, MALT1 and members of the family of CARMA proteins have recently been the focus of much attention because they represent a key mechanism for regulating activation of the transcription factor NF-κB. Here, we report the functional characterization of a novel isoform of BCL10 in the trout Oncorhynchus mykiss, which we named tBCL10. tBCL10 dimerizes, binds to components of the CBM complex and forms cytoplasmic filaments. Functionally, tBCL10 activates NF-κB transcription factor and is inhibited by the deubiquitinating enzyme A20. Finally, depletion experiments indicate that tBCL10 can functionally replace the human protein. This work demonstrates the evolutionary conservation of the mechanism of NF-κB activation through the CBM complex, and indicates that the rainbow trout O.mykiss can serve as a model organism to study this pathway. PMID:25834783

  6. [Food effects on some reproductive aspects of rainbow trout, Oncorhynchus mykiss, in a Venezuelan fish farm].

    PubMed

    Bastardo, H

    1999-12-01

    Samples of rainbow trout, Oncorhynchus mykiss, were fed with three different dried diets, labeled D1, D2 and D3, the first ones were expanded and the last one pelleted type food. Their protein content ranged from 36% to 42%, and only D1 diet presented a pigment in its composition. The gonodasomatic index (GSI) as well as the gonadial development showed a different behavior in males and females for all the samples tested. A continuous sperm production was observed in males fish, while in female fish the GSI showed a tendency to increase through the whole study, and they showed a reproductive rest period on july 92. Fish relative fecundity and egg diameter were similar in all cases. The gonodial maduration age was shorter for the female that were fed with D1 and D2, while the 50% of the trout population that got D3 had a gonodial maduration period two months longer. For all trouts tested the fertility was low with a maximum value of 49%. The hatchery from the tested trouts with D2 intakes had a mortality value of 62%. Meanwhile, those with D1 and D3 intakes showed mortality values of 36% and 43% respectively. PMID:10883303

  7. Growth of juvenile steelhead Oncorhynchus mykiss under size-selective pressure limited by seasonal bioenergetic and environmental constraints.

    PubMed

    Thompson, J N; Beauchamp, D A

    2016-09-01

    Increased freshwater growth of juvenile steelhead Oncorhynchus mykiss improved survival to smolt and adult stages, thus prompting an examination of factors affecting growth during critical periods that influenced survival through subsequent life stages. For three tributaries with contrasting thermal regimes, a bioenergetics model was used to evaluate how feeding rate and energy density of prey influenced seasonal growth and stage-specific survival of juvenile O. mykiss. Sensitivity analysis examined target levels for feeding rate and energy density of prey during the growing season that improved survival to the smolt and adult stages in each tributary. Simulated daily growth was greatest during warmer months (1 July to 30 September), whereas substantial body mass was lost during cooler months (1 December to 31 March). Incremental increases in annual feeding rate or energy density of prey during summer broadened the temperature range at which faster growth occurred and increased the growth of the average juvenile to match those that survived to smolt and adult stages. Survival to later life stages could be improved by increasing feeding rate or energy density of the diet during summer months, when warmer water temperatures accommodated increased growth potential. Higher growth during the summer period in each tributary could improve resiliency during subsequent colder periods that lead to metabolic stress and weight loss. As growth and corresponding survival rates in fresh water are altered by shifting abiotic regimes, it will be increasingly important for fisheries managers to better understand the mechanisms affecting growth limitations in rearing habitats and what measures might maintain or improve growth conditions and survival. PMID:27397641

  8. Growth of juvenile steelhead Oncorhynchus mykiss under size-selective pressure limited by seasonal bioenergetic and environmental constraints

    USGS Publications Warehouse

    Thompson, Jamie N.; Beauchamp, David A.

    2016-01-01

    Increased freshwater growth of juvenile steelhead Oncorhynchus mykiss improved survival to smolt and adult stages, thus prompting an examination of factors affecting growth during critical periods that influenced survival through subsequent life stages. For three tributaries with contrasting thermal regimes, a bioenergetics model was used to evaluate how feeding rate and energy density of prey influenced seasonal growth and stage-specific survival of juvenile O. mykiss. Sensitivity analysis examined target levels for feeding rate and energy density of prey during the growing season that improved survival to the smolt and adult stages in each tributary. Simulated daily growth was greatest during warmer months (1 July to 30 September), whereas substantial body mass was lost during cooler months (1 December to 31 March). Incremental increases in annual feeding rate or energy density of prey during summer broadened the temperature range at which faster growth occurred and increased the growth of the average juvenile to match those that survived to smolt and adult stages. Survival to later life stages could be improved by increasing feeding rate or energy density of the diet during summer months, when warmer water temperatures accommodated increased growth potential. Higher growth during the summer period in each tributary could improve resiliency during subsequent colder periods that lead to metabolic stress and weight loss. As growth and corresponding survival rates in fresh water are altered by shifting abiotic regimes, it will be increasingly important for fisheries managers to better understand the mechanisms affecting growth limitations in rearing habitats and what measures might maintain or improve growth conditions and survival.

  9. Continuous Exposure to Infectious Pancreatic Necrosis Virus (IPNV) During Early Life Stages of Rainbow Trout, Oncorhynchus mykiss, Walbaum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rainbow trout (Oncorhynchus mykiss, Walbaum) were exposed continuously to infectious pancreatic necrosis virus (IPNV) at 0, 10, 1,000, or 10,000 pfu/L of water to estimate the effects of chronic IPNV exposure on early life stages. Fish density averaged 35 fish/L (low) or 140 fish/L (high), and wate...

  10. Continuous exposure to infectious pancreatic necrosis virus during early life stages of rainbow trout, Oncorhynchus mykiss(Walbaum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rainbow trout (Oncorhynchus mykiss, Walbaum) were exposed continuously to infectious pancreatic necrosis virus (IPNV) at 0, 10, 1,000, or 100,000 pfu/L of water to estimate the effects of chronic IPNV exposure on early life stages. Fish density averaged 35 fish/L or 140 fish/L, with a tank flow rat...

  11. Abnormal swimming behavior and increased deformities in rainbow trout Oncorhynchus mykiss cultured in low exchange water recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two studies were conducted to determine if accumulating water quality parameters would negatively impact rainbow trout Oncorhynchus mykiss health and welfare within water recirculation aquaculture systems (WRAS) that were operated at low and near-zero water exchange, with and without ozonation, and ...

  12. Enhancing highly unsaturated omega-3 fatty acids in phase-fed rainbow trout (Oncorhynchus mykiss) using Alaskan fish oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to investigate differences in the kinetics of fatty acids (FA) deposition in fillets of market-sized (approximately 450g) rainbow trout (Oncorhynchus mykiss) fed diets containing commercial Alaskan fish oils versus menhaden oil. Comparisons were made with FA leve...

  13. Acute handling disturbance modulates plasma insulin-like growth factor binding proteins in rainbow trout (Oncorhynchus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of acute stressor exposure on proximal (growth hormone; GH) and distal (insulin-like growth factor-I; IGF-I and IGF-binding proteins) components of the somatotropic axis are poorly understood in finfish. We exposed rainbow trout (Oncorhynchus mykiss) to a 5-minute handling disturbance to...

  14. A second generation integrated map of the rainbow trout (Oncorhynchus mykiss) genome: analysis of synteny with model fish genomes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper we generated DNA fingerprints and end sequences from bacterial artificial chromosomes (BACs) from two new libraries to improve the first generation integrated physical and genetic map of the rainbow trout (Oncorhynchus mykiss) genome. The current version of the physical map is compose...

  15. Effect of anthocyanidins on myogenic differentiation in induced and non-induced primary myoblasts from rainbow trout (Oncorhynchus mykiss).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to test whether an anthocyanidin mixture (peonidin, cyanidin and pelargonidin chloride) modulates myogenesis in both induced and non-induced myogenic cells from juvenile rainbow trout (Oncorhynchus mykiss). We evaluated three different anthocyanidin concentrations (1X, 2.5X and...

  16. Willingness-to-pay for steelhead trout fishing: Implications of two-step consumer decisions with short-run endowments

    NASA Astrophysics Data System (ADS)

    McKean, John R.; Johnson, Donn; Taylor, R. Garth

    2010-09-01

    Choice of the appropriate model of economic behavior is important for the measurement of nonmarket demand and benefits. Several travel cost demand model specifications are currently in use. Uncertainty exists over the efficacy of these approaches, and more theoretical and empirical study is warranted. Thus travel cost models with differing assumptions about labor markets and consumer behavior were applied to estimate the demand for steelhead trout sportfishing on an unimpounded reach of the Snake River near Lewiston, Idaho. We introduce a modified two-step decision model that incorporates endogenous time value using a latent index variable approach. The focus is on the importance of distinguishing between short-run and long-run consumer decision variables in a consistent manner. A modified Barnett two-step decision model was found superior to other models tested.

  17. Copper binding affinity of rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) gills: Implications for assessing bioavailable metal

    SciTech Connect

    MacRae, R.K.; Smith, D.E.; Swoboda-Colberg, N.; Meyer, J.S.; Bergman, H.L. . Dept. of Zoology and Physiology)

    1999-06-01

    In this study, the authors determined the conditional stability constant (log K[prime]) of copper for the gills of rainbow trout (Oncorhynchus mykiss; RBT) and brook trout (Salvelinus fontinalis; BT). Using toxicity-based complexation bioassays, which measure the effect of competing organic ligands on copper toxicity, the RBT gill copper log K[prime] range was 6.4 to 7.2. Using a Scatchard analysis of gill Cu accumulation, the RBT log K[prime] was 7.50 and the BT log K[prime] was 7.25. The close agreement in RBT log K[prime] values between these two methods suggests that measurement of gill copper accumulation is an acceptable alternative for determining a toxicity-based gill copper binding affinity. The results also suggest that there is either a single gill copper binding component or, more realistically, multiple components with similar binding properties that function collectively to define a single toxicologically relevant copper conditional stability constant. These results suggest analytical approaches to measuring bioavailable metal concentrations, such as geochemical modeling where biological ligands are included in speciation calculations, may adequately simulate complex biological ligands. A method to convert gill copper accumulation to a bioavailable water criterion is also discussed.

  18. The effects of copper on blood and biochemical parameters of rainbow trout (Oncorhynchus mykiss)

    USGS Publications Warehouse

    Dethloff, G.M.; Schlenk, D.; Khan, S.; Bailey, H.C.

    1999-01-01

    Metals are released into aquatic systems from many sources, often at sublethal concentrations. The effects of sublethal concentrations of metals on fish are not entirely understood. The objective of this study was to determine the hematological and biochemical effects of a range of copper concentrations (6.4, 16.0, 26.9 ??g Cu/L) on rainbow trout (Oncorhynchus mykiss) over a prolonged period of time. Trout were exposed to copper, and, at intervals of 3, 7, 14, and 21 days, selected parameters were evaluated. Hemoglobin, hematocrit, plasma glucose, and plasma cortisol levels were elevated in trout exposed to 26.9 ??g Cu/L at day 3 and then returned to levels comparable to control fish. Plasma protein and lactate levels were not significantly altered in trout from any copper treatment. Hepatic copper concentration and hepatic metallothionein mRNA expression were consistently elevated in trout exposed to 26.9 ??g Cu/L. Both of these parameters stabilized by day 3, with only hepatic copper concentration showing a further increase at day 21. Hepatic copper concentration and hepatic metallothionein mRNA expression appear to be robust indicators of copper exposure. Most blood-based parameters evaluated appear to be associated with a transitory, nonspecific stress response. The return of elevated hematological and biochemical parameters to control levels after 3 days and thestabilization of hepatic metallothionein mRNA expression and copper concentration over a similar time period suggested acclimation to dissolved copper at 26.9 ??g/L. Further analysis of the data on blood-based parameters indicated that certain parameters (hemoglobin, hematocrit, plasma glucose, plasma cortisol) may be useful in field monitoring.

  19. Effects of deltamethrin on excitability and contractility of the rainbow trout (Oncorhynchus mykiss) heart.

    PubMed

    Haverinen, Jaakko; Vornanen, Matti

    2014-01-01

    Pyrethroids are extensively used for the control of pest insects and disease vectors. Pyrethroid use is regarded safe due to their selective toxicity: they are effective against insects but relatively harmless to mammals and birds. Unfortunately, pyrethroids are very toxic to fishes. The high toxicity of pyrethroids to fishes is only partly explained by slow elimination rate of toxins, suggesting that high affinity binding to their molecular targets, the Na(+) channels, is involved. This study tests the hypothesis that Na(+) channels of the fish heart are targets to a type II pyrethroid, deltamethrin (DM), and therefore pyrethroids are cardiotoxic to fishes. In ventricular myocytes of the rainbow trout (Oncorhynchus mykiss) heart DM (10(-7)-3·10(-5) M) modified Na(+) current by slowing inactivation and shifting the reversal potential of the current to the left. Maximally 31±2% of the cardiac Na(+) channels were modified by DM and the half-maximal effect occurred at the concentration of 2.1 μM. The effect of DM on trout cardiac Na(+) channels is stronger and occurs about an order of magnitude lower in concentration in comparison to the orthologous mammalian Na(+) channels. In sinoatrial preparations of the trout heart DM (10 μM) caused irregularities in rate, rhythm and force of the heartbeat indicating that DM can be arrhythmogenic for the trout heart. Consistent with this, DM (>0.1 μM) induced spontaneous action potentials in otherwise quiescent ventricular myocytes. DM (10 μM) did not affect calcium current or inward rectifier and delayed rectifier potassium currents. Collectively, these findings indicate that DM exerts cardiotoxic effects in trout, and suggest that the high sensitivity of fishes to pyrethroid toxicity might be partially due to the high affinity of fish Na(+) channels to pyrethroids. PMID:24100050

  20. Identification of differentially expressed genes of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in response to Tetracapsuloides bryosalmonae (Myxozoa).

    PubMed

    Kumar, Gokhlesh; Abd-Elfattah, Ahmed; El-Matbouli, Mansour

    2015-03-01

    Tetracapsuloides bryosalmonae Canning et al., 1999 (Myxozoa) is the causative agent of proliferative kidney disease in various species of salmonids in Europe and North America. We have shown previously that the development and distribution of the European strain of T. bryosalmonae differs in the kidney of brown trout (Salmo trutta) Linnaeus, 1758 and rainbow trout (Oncorhynchus mykiss) Walbaum, 1792, and that intra-luminal sporogonic stages were found in brown trout but not in rainbow trout. We have now compared transcriptomes from kidneys of brown trout and rainbow trout infected with T. bryosalmonae using suppressive subtractive hybridization (SSH). The differentially expressed transcripts produced by SSH were cloned, transformed, and tested by colony PCR. Differential expression screening of PCR products was validated using dot blot, and positive clones having different signal intensities were sequenced. Differential screening and a subsequent NCBI-BLAST analysis of expressed sequence tags revealed nine clones expressed differently between both fish species. These differentially expressed genes were validated by quantitative real-time PCR of kidney samples from both fish species at different time points of infection. Expression of anti-inflammatory (TSC22 domain family protein 3) and cell proliferation (Prothymin alpha) genes were upregulated significantly in brown trout but downregulated in rainbow trout. The expression of humoral immune response (immunoglobulin mu) and endocytic pathway (Ras-related protein Rab-11b) genes were significantly upregulated in rainbow trout but downregulated in brown trout. This study suggests that differential expression of host anti-inflammatory, humoral immune and endocytic pathway responses, cell proliferation, and cell growth processes do not inhibit the development of intra-luminal sporogonic stages of the European strain of T. bryosalmonae in brown trout but may suppress it in rainbow trout. PMID:25563603

  1. Coupled stream and population dynamics: Modeling the role beaver (Castor canadensis) play in generating juvenile steelhead (Oncorhynchus mykiss) habitat

    NASA Astrophysics Data System (ADS)

    Jordan, C.; Bouwes, N.; Wheaton, J. M.; Pollock, M.

    2013-12-01

    Over the past several centuries, the population of North American Beaver has been dramatically reduced through fur trapping. As a result, the geomorphic impacts long-term beaver occupancy and activity can have on fluvial systems have been lost, both from the landscape and from our collective memory such that physical and biological models of floodplain system function neither consider nor have the capacity to incorporate the role beaver can play in structuring the dynamics of streams. Concomitant with the decline in beaver populations was an increasing pressure on streams and floodplains through human activity, placing numerous species of stream rearing fishes in peril, most notably the ESA listing of trout and salmon populations across the entirety of the Western US. The rehabilitation of stream systems is seen as one of the primary means by which population and ecosystem recovery can be achieved, yet the methods of stream rehabilitation are applied almost exclusively with the expected outcome of a static idealized stream planform, occasionally with an acknowledgement of restoring processes rather than form and only rarely with the goal of a beaver dominated riverscape. We have constructed an individual based model of trout and beaver populations that allows the exploration of fish population dynamics as a function of stream habitat quality and quantity. We based the simulation tool on Bridge Creek (John Day River basin, Oregon) where we have implemented a large-scale restoration experiment using wooden posts to provide beavers with stable platforms for dam building and to simulate the dams themselves. Extensive monitoring captured geomorphic and riparian changes, as well as fish and beaver population responses; information we use to parameterize the model as to the geomorphic and fish response to dam building beavers. In the simulation environment, stream habitat quality and quantity can be manipulated directly through rehabilitation actions and indirectly

  2. Compensatory growth response of rainbow trout Oncorhynchus mykiss Walbaum following short starvation periods

    NASA Astrophysics Data System (ADS)

    Azodi, Maryam; Ebrahimi, Eisa; Farhadian, Omidvar; Mahboobi-Soofiani, Nasrollah; Morshedi, Vahid

    2015-07-01

    This sixty-day study was performed to determine the effects of short-term starvation and re-feeding cycles on growth, feeding performances and body composition of rainbow trout ( Oncorhynchus mykiss). Three hundred trout fingerlings with an average initial weight of 17.5±0.06 g were randomly distributed in 15 circular fiberglass tanks. The fish were exposed to 5 different feeding regimes; control: continuously fed twice daily to apparent satiation; T1: starved for 1 day and re-fed for 2 days; T2: starved for 1 day and re-fed for 4 days; T3: starved for 3 days and re-fed for 12 days; T4: starved for 4 days and re-fed for 16 days. At the end of the experiment, growth performance, feed utilization, whole body ash and moisture contents were not significantly ( P>0.05) different among the treatments. However, whole body protein content in T3 was significantly higher than other treatments ( P<0.05). A significant difference in whole body fat content was observed between T3 and the control group at the end of the experiment ( P<0.05). In conclusion this experiment suggests that feeding schedules involving starvation (1-4 days) and re-feeding cycles are a promising feed management tool for rainbow trout culture.

  3. Behaviour of rainbow trout ( Oncorhynchus mykiss) under defensible and indefensible patterns of food delivery

    NASA Astrophysics Data System (ADS)

    Saeed Heydarnejad, M.; Purser, G. J.

    2010-07-01

    The goal of this study was to investigate the behaviour of rainbow trout ( n=30), Oncorhynchus mykiss, in small raceways when either self-feeders (T2) or hand-feeding (t2) were used. The method of food delivery in T2 was defensible while that of t2 was indefensible. Fish in both raceways were subjected to restricted feeding (RF) for 25 days. Food was available in the morning (09:00-10:00) in the downstream area and in the afternoon (16:00-17:00) in the upstream area of the raceways. The results showed that the behaviour of rainbow trout was significantly different under interference competition (T2) for food compared with that under scramble competition (t2). RF in T2 fish limited food availability to meal times when feeding rewards were available while t2 fish only responded to the location of food delivery. The aggressive fish in T2 were dominant, and t2 fish at high densities showed intense social interactions under the indefensible pattern of food distribution; these interactions did not dampen to a minimum level to suppress the development of dominance hierarchies. Further, the stocking density did not break down the dominance hierarchies between the T2 fish. This suggests that decreased efficiency in the search for food or inefficient foraging, induced by interference competition at high densities, affected the behaviour of rainbow trout.

  4. Mechanisms of fenthion activation in rainbow trout (Oncorhynchus mykiss) acclimated to hypersaline environments

    PubMed Central

    Lavado, Ramon; Rimoldi, John M.; Schlenk, Daniel

    2010-01-01

    Previous studies in rainbow trout have shown that acclimation to hypersaline environments enhances the toxicity to thioether organophosphate and carbamate pesticides. In order to determine the role of biotransformation in this process, the metabolism of the thioether organophosphate biocide, fenthion was evaluated in microsomes from gills, liver and olfactory tissues in rainbow trout (Oncorhynchus mykiss) acclimated to freshwater and 17‰ salinity. Hypersalinity acclimation increased the formation of fenoxon and fenoxon sulfoxide from fenthion in liver microsomes from rainbow trout, but not in gills or in olfactory tissues. NADPH-dependent and independent hydrolysis was observed in all tissues, but only NADPH-dependent fenthion cleavage was differentially modulated by hypersalinity in liver (inhibited) and gills (induced). Enantiomers of fenthion sulfoxide (65% and 35% R- and S-fenthion sulfoxide, respectively) were formed in liver and gills. The predominant pathway of fenthion activation in freshwater appears to be initiated through initial formation of fenoxon which may be subsequently converted to the most toxic metabolite fenoxon R-sulfoxide. However, in hypersaline conditions both fenoxon and fenthion sulfoxide formation may precede fenoxon sulfoxide formation. Stereochemical evaluation of sulfoxide formation, cytochrome P450 inhibition studies with ketoconazole and immunoblots indicated that CYP3A27 was primarily involved in the enhancement of fenthion activation in hypersaline-acclimated fish with limited contribution of FMO to initial sulfoxidation. PMID:19111563

  5. Thyroid signaling in immune organs and cells of the teleost fish rainbow trout (Oncorhynchus mykiss).

    PubMed

    Quesada-García, A; Valdehita, A; Kropf, C; Casanova-Nakayama, A; Segner, H; Navas, J M

    2014-05-01

    Thyroid hormones are involved in modulating the immune system in mammals. In contrast, there is no information on the role played by these hormones in the immune system of teleost fish. Here we provide initial evidence for the presence of active thyroid signaling in immune organs and cells of teleosts. We demonstrate that immune organs (head kidney and spleen) and isolated leukocytes (from head kidney and peripheral blood) of the rainbow trout (Oncorhynchus mykiss) express both thyroid receptor α (THRA) and β (THRB). Absolute mRNA levels of THRA were significantly higher than those of THRB. THRA showed higher expression in immune organs and isolated immune cells compared to the reference organ, liver, while THRB showed the opposite. In vivo exposure of trout to triiodothryronine (T3) or the anti-thyroid agent propylthiouracil (PTU) altered THR expression in immune organs and cells. Effect of T3 and PTU over the relative expression of selected marker genes of immune cell subpopulations was also studied. Treatments changed the relative expression of markers of cytotoxic, helper and total T cells (cd4, cd8a, trb), B lymphocytes (mIgM) and macrophages (csf1r). These findings suggest that the immune system of rainbow trout is responsive to thyroid hormones. PMID:24657316

  6. Qualitative modification of muscle metabolic organization with thermal acclimation of rainbow trout, Oncorhynchus mykiss.

    PubMed

    Guderley, H; Gawlicka, A

    1992-08-01

    Rainbow trout (Oncorhynchus mykiss) were acclimated to 4 and 18°C and fed at rations levels which led to an equal change in mass at these temperatures during the six week acclimation. Thermal acclimation markedly modified the metabolic organization of red and white muscle. Cold-acclimated fish had activities of β-hydroxyacyl CoA dehydrogenase in both red and white muscle that were twice those of warm-acclimated fish. By contrast, the activities of cytochrome oxidase were unchanged by thermal acclimation. Thus, the capacity for β-oxidation of lipids is specifically enhanced in the muscle of cold-acclimated trout. In white muscle, citrate synthase and phosphofructokinase activities were also enhanced by cold acclimation (increases of 125% and 35% respectively), while cytochrome oxidase levels were unchanged. The non-parallel changes in the activities of mitochondrial enzymes strongly suggest that trout muscle mitochondria undergo qualitative reorganization during cold acclimation. The relative activities of mitochondrial enzymes suggest that mitochondria from red muscle have a threefold greater capacity to oxidize lipids than those from white muscle. PMID:24214209

  7. Mechanisms of fenthion activation in rainbow trout (Oncorhynchus mykiss) acclimated to hypersaline environments

    SciTech Connect

    Lavado, Ramon Rimoldi, John M.; Schlenk, Daniel

    2009-03-01

    Previous studies in rainbow trout have shown that acclimation to hypersaline environments enhances the toxicity to thioether organophosphate and carbamate pesticides. In order to determine the role of biotransformation in this process, the metabolism of the thioether organophosphate biocide, fenthion was evaluated in microsomes from gills, liver and olfactory tissues in rainbow trout (Oncorhynchus mykiss) acclimated to freshwater and 17 per mille salinity. Hypersalinity acclimation increased the formation of fenoxon and fenoxon sulfoxide from fenthion in liver microsomes from rainbow trout, but not in gills or in olfactory tissues. NADPH-dependent and independent hydrolysis was observed in all tissues, but only NADPH-dependent fenthion cleavage was differentially modulated by hypersalinity in liver (inhibited) and gills (induced). Enantiomers of fenthion sulfoxide (65% and 35% R- and S-fenthion sulfoxide, respectively) were formed in liver and gills. The predominant pathway of fenthion activation in freshwater appears to be initiated through initial formation of fenoxon which may be subsequently converted to the most toxic metabolite fenoxon R-sulfoxide. However, in hypersaline conditions both fenoxon and fenthion sulfoxide formation may precede fenoxon sulfoxide formation. Stereochemical evaluation of sulfoxide formation, cytochrome P450 inhibition studies with ketoconazole and immunoblots indicated that CYP3A27 was primarily involved in the enhancement of fenthion activation in hypersaline-acclimated fish with limited contribution of FMO to initial sulfoxidation.

  8. A novel role for pigment genes in the stress response in rainbow trout (Oncorhynchus mykiss)

    PubMed Central

    Khan, Uniza Wahid; Øverli, Øyvind; Hinkle, Patricia M.; Pasha, Farhan Ahmad; Johansen, Ida Beitnes; Berget, Ingunn; Silva, Patricia I. M.; Kittilsen, Silje; Höglund, Erik; Omholt, Stig W.; Våge, Dag Inge

    2016-01-01

    In many vertebrate species visible melanin-based pigmentation patterns correlate with high stress- and disease-resistance, but proximate mechanisms for this trait association remain enigmatic. Here we show that a missense mutation in a classical pigmentation gene, melanocyte stimulating hormone receptor (MC1R), is strongly associated with distinct differences in steroidogenic melanocortin 2 receptor (MC2R) mRNA expression between high- (HR) and low-responsive (LR) rainbow trout (Oncorhynchus mykiss). We also show experimentally that cortisol implants increase the expression of agouti signaling protein (ASIP) mRNA in skin, likely explaining the association between HR-traits and reduced skin melanin patterning. Molecular dynamics simulations predict that melanocortin 2 receptor accessory protein (MRAP), needed for MC2R function, binds differently to the two MC1R variants. Considering that mRNA for MC2R and the MC1R variants are present in head kidney cells, we hypothesized that MC2R activity is modulated in part by different binding affinities of the MC1R variants for MRAP. Experiments in mammalian cells confirmed that trout MRAP interacts with the two trout MC1R variants and MC2R, but failed to detect regulation of MC2R signaling, possibly due to high constitutive MC1R activity. PMID:27373344

  9. A novel role for pigment genes in the stress response in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Khan, Uniza Wahid; Øverli, Øyvind; Hinkle, Patricia M; Pasha, Farhan Ahmad; Johansen, Ida Beitnes; Berget, Ingunn; Silva, Patricia I M; Kittilsen, Silje; Höglund, Erik; Omholt, Stig W; Våge, Dag Inge

    2016-01-01

    In many vertebrate species visible melanin-based pigmentation patterns correlate with high stress- and disease-resistance, but proximate mechanisms for this trait association remain enigmatic. Here we show that a missense mutation in a classical pigmentation gene, melanocyte stimulating hormone receptor (MC1R), is strongly associated with distinct differences in steroidogenic melanocortin 2 receptor (MC2R) mRNA expression between high- (HR) and low-responsive (LR) rainbow trout (Oncorhynchus mykiss). We also show experimentally that cortisol implants increase the expression of agouti signaling protein (ASIP) mRNA in skin, likely explaining the association between HR-traits and reduced skin melanin patterning. Molecular dynamics simulations predict that melanocortin 2 receptor accessory protein (MRAP), needed for MC2R function, binds differently to the two MC1R variants. Considering that mRNA for MC2R and the MC1R variants are present in head kidney cells, we hypothesized that MC2R activity is modulated in part by different binding affinities of the MC1R variants for MRAP. Experiments in mammalian cells confirmed that trout MRAP interacts with the two trout MC1R variants and MC2R, but failed to detect regulation of MC2R signaling, possibly due to high constitutive MC1R activity. PMID:27373344

  10. Imprinting Salmon and Steelhead Trout for Homing, 1981 Annual Report of Research.

    SciTech Connect

    Slatick, Emil

    1982-09-01

    The National Marine Fisheries Service, under contract to the Bonneville Power Administration, began conducting research on imprinting Pacific salmon and steelhead for homing in 1978. The juvenile marking phase was completed in 1980; over 4 million juvenile salmon and steelhead were marked and released in 23 experiments. The primary objectives were to determine: (1) a triggering mechanism to activate the homing imprint, (2) if a single imprint or a sequential imprint is necessary to assure homing, and (3) the relationship between the physiological condition of fish and their ability to imprint. Research in 1981 concentrated on: (1) recovering returning adults from previous experiments, (2) analyzing completed 1978 steelhead and 1980 coho salmon experiments, and (3) preliminary analyzing 1979 and 1980 fall chinook salmon experiments. Seven experimental groups are discussed: four steelhead, two fall chinook salmon, and one coho salmon. In four groups, survival was enhanced by the imprinting-transportation procedures. Homing back to the hatchery area was successful in two groups, and generally, unless there were extenuating circumstances (eruption of Mount St. Helens, disease problem, etc.), greater returns to user groups were evident.

  11. Imprinting Salmon and Steelhead Trout for Homing, 1982 Annual Report of Research.

    SciTech Connect

    Slatick, Emil

    1983-11-01

    The National Marine Fisheries Service, under contract to the Bonneville Power Administration, began conducting research on imprinting Pacific salmon and steelhead for homing in 1978. The juvenile marking phase was completed in 1980; over 4 million juvenile salmon and steelhead were marked and released in 23 experiments. The primary objectives were to determine; (1) a triggering mechanism to activate the homing imprint, (2) if a single imprint or a sequential imprint is necessary to assure homing, and (3) the relationship between the physiological condition of fish and their ability to imprint. Research in 1982 concentrated on: (1) recovering returning adults from previous experiments, (2) analyzing completed 1979 steelhead and chinook salmon experiments, and (3) preliminarily analyzing 1980 fall chinook salmon experiments. Six experimental groups are discussed: two steelhead, two spring chinook salmon, and two fall chinook salmon. In four test groups, survival was enhanced by the imprinting-transportation procedures. Homing back to the hatchery area was partly successful in two test groups, and generally, unless there were extenuating circumstances (eruption of Mount St. Helens, disease problem, etc.), greater returns to user groups were evident.

  12. CRITICAL EVALUATION OF A NEW MULTIPLEX SYSTEM USED FOR PARENTAL ALLOCATION AND BROODSTOCK MANAGEMENT IN RAINBOW TROUT (Oncorhynchus mykiss) SELECTION PROGRAMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Examination of microsatellite variation at several polymorphic loci is the predominant method for determining parentage and examining genetic diversity within rainbow trout (Oncorhynchus mykiss). The genotyping costs associated with these analyses are considerable for large-scale commercial breedin...

  13. Intensive Evaluation and Monitoring of Chinook Salmon and Steelhead Trout Production, Crooked River and Upper Salmon River Sites, 1995 Annual Report.

    SciTech Connect

    Kiefer, Russell B.; Lockhart, Jerald N.

    1999-10-01

    The purpose of this intensive monitoring project is to determine the number of returning chinook salmon and steelhead trout adults necessary to achieve optimal smolt production and develop habitat enhancement mitigation accounting based on increases in wild/natural smolt production. Two locations in Idaho are being intensively studied to meet these objectives. Information from this research will be applied to parr monitoring streams statewide to develop escapement objectives and determine success of habitat enhancement projects. The project to date has developed good information on the relationship between chinook salmon adult escapement and smolt production at low to medium seeding levels. Adult chinook salmon escapements have been too low for us to test carrying capacity. For steelhead trout, they have developed a relationship between parr populations and smolt production at low to high seeding levels, with limited information on carrying capacity.

  14. Colonization of steelhead in a natal stream after barrier removal

    USGS Publications Warehouse

    Weigel, Dana E.; Connolly, Patrick J.; Martens, Kyle D.; Powell, Madison S.

    2013-01-01

    Colonization of vacant habitats is an important process for supporting the long-term persistence of populations and species. We used a before–after experimental design to follow the process of colonization by steelhead Oncorhynchus mykiss (anadromous Rainbow Trout) at six monitoring sites in a natal stream, Beaver Creek, after the modification or removal of numerous stream passage barriers. Juvenile O. mykiss were collected at monitoring sites by using a backpack electrofisher. Passive integrated transponder tags and instream tag reading stations were used in combination with 16 microsatellite markers to determine the source, extent, and success of migrant O. mykiss after implementation of the barrier removal projects. Steelhead migrated into the study area during the first spawning season after passage was established. Hatchery steelhead, although comprising more than 80% of the adult returns to the Methow River basin, constituted a small proportion (23%) of the adult O. mykiss colonizing the study area. Adult steelhead and fluvial Rainbow Trout entered the stream during the first spawning season after barrier removal and were passing the uppermost tag reader (12 km upstream from the mouth) 3–4 years later. Parr that were tagged in Beaver Creek returned as adults, indicating establishment of the anadromous life history in the study area. Population genetic measures at the lower two monitoring sites (lower 4 km of Beaver Creek) significantly changed within one generation (4–5 years). Colonization and expansion of steelhead occurred more slowly than expected due to the low number of adults migrating into the study area.

  15. Effect of iprodione, a dicarboximide fungicide, on primary cultured rainbow trout (Oncorhynchus mykiss) hepatocytes.

    PubMed

    Radice, S; Ferraris, M; Marabini, L; Grande, S; Chiesara, E

    2001-09-01

    As is known from literature, iprodione, a dicarboximide fungicide, has a highly specific action, with a capacity to cause oxidative damage through production of free oxygen radicals (ROS), but it does not appear to be species selective. Since this substance is able to diffuse in water, evaluation of its capacity to induce oxidative damage in an aquatic organism such as the rainbow trout (Oncorhynchus mykiss) was considered of particular interest. A study was, therefore, undertaken to investigate the effect of iprodione on free radicals (ROS) and malondialdehyde (MDA) production, reduced glutathione (GSH) content and catalase activity (CAT), in primary cultured trout hepatocytes, following treatment with 0.2, 0.3 and 0.4 mM concentrations for a 24-h period. The iprodione 0.3 and 0.4 mM concentrations increased both ROS and MDA production and decreased GSH content and CAT activity. These results suggest that iprodione is able to produce oxidative damage in primary cultured fish hepatocytes, thus confirming that its action is specific, but not species selective. It is also well known that ROS production in fungi is due to interaction with the flavin enzyme NADPH cytochrome c reductase to the extent that the normal electron flow from NADPH to cytochrome c is blocked. In contrast, we observed that, in primary cultured trout hepatocytes, iprodione appears to have no effect on NADPH cytochrome c reductase activity. It is, therefore, possible to presume that the mechanism of oxidative damage in trout hepatocytes differs from that observed in fungi. Moreover, our experiments also demonstrate that iprodione is able to induce "in vitro" CYP1A1, leading to the conclusion that the production of ROS is due to this phenomenon. PMID:11451425

  16. Effects of aquaculture production noise on hearing, growth, and disease resistance of rainbow trout Oncorhynchus mykiss

    USGS Publications Warehouse

    Wysocki, L.E.; Davidson, J. W., III; Smith, M.E.; Frankel, A.S.; Ellison, W.T.; Mazik, P.M.; Popper, A.N.; Bebak, J.

    2007-01-01

    Intensive aquaculture production often utilizes equipment (e.g., aerators, air and water pumps, harvesters, blowers, filtration systems, and maintenance machinery) that increases noise levels in fish culture tanks. Consequently, chronic exposure to elevated noise levels in tanks could negatively impact cultured species. Possible effects include impairment of the auditory system, increased stress, and reduced growth rates. The objective of this study was to evaluate the long-term effects of sound exposure on the hearing sensitivity, growth, and survival of cultured rainbow trout (Oncorhynchus mykiss). Two cohorts of rainbow trout were cultured for 8??months in replicated tanks consisting of three sound treatments: 115, 130, or 150 decibels referenced at 1 micropascal (dB re 1????Pa root mean square [RMS]) levels. Auditory evoked potential (AEP) recordings revealed no significant differences in hearing thresholds resulting from exposure to increased ambient sound levels. Although there was no evident noise-induced hearing loss, there were significant differences in hearing thresholds between the two fish cohorts examined. No statistical effect of sound treatment was found for growth rate and mortality within each fish cohort. There was no significant difference in mortality between sound treatments when fish were exposed to the pathogen Yersinia ruckeri, but there was significantly different mortality between cohorts. This study indicated that rainbow trout hearing sensitivity, growth, survival, stress, and disease susceptibility were not negatively impacted by noise levels common to recirculating aquaculture systems. These findings should not be generalized to all cultured fish species, however, because many species, including catfish and cyprinids, have much greater hearing sensitivity than rainbow trout and could be affected differently by noise. ?? 2007 Elsevier B.V. All rights reserved.

  17. Spatial ecological processes and local factors predict the distribution and abundance of spawning by steelhead (Oncorhynchus mykiss) across a complex riverscape

    USGS Publications Warehouse

    Falke, Jeffrey A.; Dunham, Jason B.; Jordan, Christopher E.; McNyset, Kris M.; Reeves, Gordon H.

    2013-01-01

    Processes that influence habitat selection in landscapes involve the interaction of habitat composition and configuration and are particularly important for species with complex life cycles. We assessed the relative influence of landscape spatial processes and local habitat characteristics on patterns in the distribution and abundance of spawning steelhead (Oncorhynchus mykiss), a threatened salmonid fish, across ~15,000 stream km in the John Day River basin, Oregon, USA. We used hurdle regression and a multi-model information theoretic approach to identify the relative importance of covariates representing key aspects of the steelhead life cycle (e.g., site access, spawning habitat quality, juvenile survival) at two spatial scales: within 2-km long survey reaches (local sites) and ecological neighborhoods (5 km) surrounding the local sites. Based on Akaike’s Information Criterion, models that included covariates describing ecological neighborhoods provided the best description of the distribution and abundance of steelhead spawning given the data. Among these covariates, our representation of offspring survival (growing-season-degree-days, °C) had the strongest effect size (7x) relative to other predictors. Predictive performances of model-averaged composite and neighborhood-only models were better than a site-only model based on both occurrence (percentage of sites correctly classified = 0.80±0.03 SD, 0.78±0.02 vs. 0.62±0.05, respectively) and counts (root mean square error = 3.37, 3.93 vs. 5.57, respectively). The importance of both temperature and stream flow for steelhead spawning suggest this species may be highly sensitive to impacts of land and water uses, and to projected climate impacts in the region and that landscape context, complementation, and connectivity will drive how this species responds to future environments.

  18. Spatial Ecological Processes and Local Factors Predict the Distribution and Abundance of Spawning by Steelhead (Oncorhynchus mykiss) across a Complex Riverscape

    PubMed Central

    Falke, Jeffrey A.; Dunham, Jason B.; Jordan, Christopher E.; McNyset, Kristina M.; Reeves, Gordon H.

    2013-01-01

    Processes that influence habitat selection in landscapes involve the interaction of habitat composition and configuration and are particularly important for species with complex life cycles. We assessed the relative influence of landscape spatial processes and local habitat characteristics on patterns in the distribution and abundance of spawning steelhead (Oncorhynchus mykiss), a threatened salmonid fish, across ∼15,000 stream km in the John Day River basin, Oregon, USA. We used hurdle regression and a multi-model information theoretic approach to identify the relative importance of covariates representing key aspects of the steelhead life cycle (e.g., site access, spawning habitat quality, juvenile survival) at two spatial scales: within 2-km long survey reaches (local sites) and ecological neighborhoods (5 km) surrounding the local sites. Based on Akaike’s Information Criterion, models that included covariates describing ecological neighborhoods provided the best description of the distribution and abundance of steelhead spawning given the data. Among these covariates, our representation of offspring survival (growing-season-degree-days, °C) had the strongest effect size (7x) relative to other predictors. Predictive performances of model-averaged composite and neighborhood-only models were better than a site-only model based on both occurrence (percentage of sites correctly classified = 0.80±0.03 SD, 0.78±0.02 vs. 0.62±0.05, respectively) and counts (root mean square error = 3.37, 3.93 vs. 5.57, respectively). The importance of both temperature and stream flow for steelhead spawning suggest this species may be highly sensitive to impacts of land and water uses, and to projected climate impacts in the region and that landscape context, complementation, and connectivity will drive how this species responds to future environments. PMID:24265762

  19. Movement and feeding ecology of recently emerged steelhead in Lake Ontario tributaries

    USGS Publications Warehouse

    Johnson, James H.; McKenna, James E., Jr.; Douglass, Kevin A.

    2012-01-01

    Steelhead (Oncorhynchus mykiss) ascend several Lake Ontario tributaries to spawn and juveniles are often the most abundant salmonid where spawning is successful. Movement and diet of recently emerged subyearling steelhead were examined in three New York tributaries of Lake Ontario. Downstream movement occurred mainly at night and consisted of significantly smaller fry that were feeding at lower levels than resident fry. Fry fed at the highest rate during the day and chironomids and baetids were the main components of their diet. The diet composition of steelhead fry was closely associated with the composition of the benthos in Trout Brook but more similar to the composition of the drift in the other streams. Daily ration was similar among streams, ranging from 10.2 to 14.3%. These findings are consistent with previous findings on the ecology of steelhead fry, as well as fry of other salmonid species

  20. Cholinergic and behavioral neurotoxicity of carbaryl and cadmium to larval rainbow trout (Oncorhynchus mykiss).

    PubMed

    Beauvais, S L; Jones, S B; Parris, J T; Brewer, S K; Little, E E

    2001-05-01

    Pesticides and heavy metals are common environmental contaminants that can cause neurotoxicity to aquatic organisms, impairing reproduction and survival. Neurotoxic effects of cadmium and carbaryl exposures were estimated in larval rainbow trout (RBT; Oncorhynchus mykiss) using changes in physiological endpoints and correlations with behavioral responses. Following exposures, RBT were videotaped to assess swimming speed. Brain tissue was used to measure cholinesterase (ChE) activity, muscarinic cholinergic receptor (MChR) number, and MChR affinity. ChE activity decreased with increasing concentrations of carbaryl but not of cadmium. MChR were not affected by exposure to either carbaryl or cadmium. Swimming speed correlated with ChE activity in carbaryl-exposed RBT, but no correlation occurred in cadmium-exposed fish. Thus, carbaryl exposure resulted in neurotoxicity reflected by changes in physiological and behavioral parameters measured, while cadmium exposure did not. Correlations between behavior and physiology provide a useful assessment of neurotoxicity. PMID:11386719

  1. Oral pharmacological treatments for parasitic diseases of rainbow trout Oncorhynchus mykiss. II. Gyrodactylus sp.

    PubMed

    Tojo, J L; Santamarina, M T

    1998-07-30

    A total of 24 drugs were evaluated as regards their efficacy for oral treatment of gyrodactylosis in rainbow trout Oncorhynchus mykiss. In preliminary trials, all drugs were supplied to infected fish at 40 g per kg of feed for 10 d. Twenty-two of the drugs tested (aminosidine, amprolium, benznidazole, bithionol, chloroquine, diethylcarbamazine, flubendazole, levamisole, mebendazole, metronidazole, niclosamide, nitroxynil, oxibendazole, parbendazole, piperazine, praziquantel, ronidazole, secnidazole, tetramisole, thiophanate, toltrazuril and trichlorfon) were ineffective. Triclabendazole and nitroscanate completely eliminated the infection. Triclabendazole was effective only at the screening dosage (40 g per kg of feed for 10 d), while nitroscanate was effective at dosages as low as 0.6 g per kg of feed for 1 d. PMID:9745715

  2. Inhibition of testicular growth in rainbow trout (Oncorhynchus mykiss) exposed to estrogenic alkylphenolic chemicals

    SciTech Connect

    Jobling, S.; Sumpter, J.P.; Sheahan, D.; Osborne, J.A.; Matthiessen, P.

    1996-02-01

    It is becoming evident that an increasing number of widely used industrial and agricultural chemicals are estrogenic. The biodegradation products of a major group of nonionic surfactants, the alkylphenol polyethoxylates, are one such group. Some of these chemicals are widespread aquatic pollutants, and bioconcentrate in aquatic biota. Exposure of male rainbow trout (Oncorhynchus mykiss) to four different alkylphenolic chemicals caused synthesis of vitellogenin, a process normally dependent on endogenous estrogens, and a concomitant inhibition of testicular growth. The magnitude of these estrogenic effects was dependent on the estrogenic potency of the chemical, the stage of reproductive development of the fish, and the concentration of the chemical in the water. These results support the contention that exposure of wildlife to environmentally persistent estrogenic chemicals can result in deleterious reproductive consequences.

  3. Avoidance of copper and zinc by rainbow trout Oncorhynchus mykiss pre-exposed to copper.

    PubMed

    Svecevičius, Gintaras

    2012-01-01

    Laboratory tests were conducted on 1-year-old rainbow trout Oncorhynchus mykiss in a counter-current flow, steep-gradient chamber to evaluate their ability to detect and avoid copper and zinc at concentrations of 0.1 mg Cu/L and 1 mg Zn/L, respectively, after 10-day pre-exposure to five copper sublethal concentrations ranging from 0.1 to 0.5 mg Cu/L and after 10-day re-acclimation period in clean water. Avoidance response intensity in affected fish significantly decreased with increase in pre-exposure Cu concentration. The strength of avoidance response to Cu and Zn test solutions in pre-exposed fish after re-acclimation gradually increased in a concentration-dependent order. PMID:22002177

  4. Effect of copper sulphate on the antioxidant parameters in the rainbow trout fry, Oncorhynchus mykiss.

    PubMed

    Yonar, M E; Ispir, U; Mişe Yonar, S; Kirici, M

    2016-01-01

    The aim of this study was to evaluate antioxidant responses of rainbow trout (Oncorhynchus mykiss) exposed to different concentrations of copper sulphate (CuSO4). Fish were exposed to 0 (Group I-control), 5 (Group II), 15 (Group III) and 30 µg/L (Group IV) concentrations of CuSO4 for 14 days. Liver and gills samples were collected at the end of the experiment, and analysed for their oxidant-antioxidant status, including the malondialdehyde (MDA) level, the catalase (CAT) and glutathione peroxidase (GSH-Px) activities as well as the reduced glutathione (GSH) concentration. Results obtained showed that the levels of MDA increased in tissues of fish. Compared to control, GSH level and GSH-Px and CAT activities were significantly reduced in the fish that were exposed to different concentrations of CuSO4. The result demonstrated that CuSO4 has an oxidative-stress-inducing potential in fish. PMID:27262803

  5. Cholinergic and behavioral neurotoxicity of carbaryl and cadmium to larval rainbow trout (oncorhynchus mykiss)

    USGS Publications Warehouse

    Beauvais, S.L.; Jones, S.B.; Parris, J.T.; Brewer, S.K.; Little, E.E.

    2001-01-01

    Pesticides and heavy metals are common environmental contaminants that can cause neurotoxicity to aquatic organisms, impairing reproduction and survival. Neurotoxic effects of cadmium and carbaryl exposures were estimated in larval rainbow trout (RBT; Oncorhynchus mykiss) using changes in physiological endpoints and correlations with behavioral responses. Following exposures, RBT were videotaped to assess swimming speed. Brain tissue was used to measure cholinesterase (ChE) activity, muscarinic cholinergic receptor (MChR) number, and MChR affinity. ChE activity decreased with increasing concentrations of carbaryl but not of cadmium. MChR were not affected by exposure to either carbaryl or cadmium. Swimming speed correlated with ChE activity in carbaryl-exposed RBT, but no correlation occurred in cadmium-exposed fish. Thus, carbaryl exposure resulted in neurotoxicity reflected by changes in physiological and behavioral parameters measured, while cadmium exposure did not. Correlations between behavior and physiology provide a useful assessment of neurotoxicity. ?? 2001 Academic Press.

  6. Comparative cardiovascular effects of four fishery anesthetics in spinally transected rainbow trout, Oncorhynchus mykiss

    USGS Publications Warehouse

    Fredricks, K.T.; Gingerich, W.H.; Fater, D.C.

    1993-01-01

    1. We compared the effects of four anesthetics on heart rate, dorsal and ventral aortic blood pressure, and electrocardiograms of rainbow trout (Oncorhynchus mykiss). 1. Exposure to the local anesthetics tricaine methanesulfonate (MS-222) and benzocaine hydrochloride (BZH) produced minimal cardiovascular alterations. Mean dorsal aortic pressure (DAP) decreased during exposure to MS-222, and mean DAP and mean ventral aortic pressure (VAP) increased 15% during recovery from BZH. 3. Exposure to the general anesthetic 2-phenoxyethanol (2-PE) or the hypnotic agent etomidate (ET) dramatically decreased heart rate and blood pressures and altered EKG patterns. 4. During recovery, VAP and DAP increased above baseline for an extended period. Heart rate and EKG patterns rapidly returned to normal.

  7. Effect of ellagic acid on some haematological, immunological and antioxidant parameters of rainbow trout (Oncorhynchus mykiss).

    PubMed

    Mişe Yonar, S; Yonar, M E; Yöntürk, Y; Pala, A

    2014-10-01

    In this study, effect of ellagic acid on some haematological, immunological and antioxidant parameters in the blood and various tissues of rainbow trout (Oncorhynchus mykiss) were examined. Four groups of rainbow trout were fed experimental diets containing either no ellagic acid (control) or supplemented with ellagic acid at 50 mg/kg diet (EA-50), 100 mg/kg diet (EA-100) or 150 mg/kg diet (EA-150) for 21 days. Samples of the blood and tissue (liver, kidney and spleen) were collected at the end of the experiment and analysed for their haematological profile (the red blood cell count, the haemoglobin concentration and the haematocrit level), immune response (the white blood cell count, the oxidative radical production (NBT activity), the total plasma protein and total immunoglobulin level) and oxidant/antioxidant status (the malondialdehyde level, the superoxide dismutase, catalase and glutathione peroxidase activity as well as the reduced glutathione concentration). The findings of this study demonstrated that ellagic acid had a positive effect on the haematological parameters, the immune response and the antioxidant enzyme activities of the fish. PMID:24401136

  8. Estimating westslope cutthroat trout (Oncorhynchus clarkii lewisi) movements in a river network using strontium isoscapes

    USGS Publications Warehouse

    Muhlfeld, Clint C.; Simon R. Thorrold; Thomas E. McMahon; Marotz, Brian

    2012-01-01

    We used natural variation in the strontium concentration (Sr:Ca) and isotope composition (87Sr:86Sr) of stream waters and corresponding values recorded in otoliths of westslope cutthroat trout (Oncorhynchus clarkii lewisi) to examine movements during their life history in a large river network. We found significant spatial differences in Sr:Ca and 87Sr:86Sr values (strontium isoscapes) within and among numerous spawning and rearing streams that remained relatively constant seasonally. Both Sr:Ca and 87Sr:86Sr values in the otoliths of juveniles collected from nine natal streams were highly correlated with those values in the ambient water. Strontium isoscapes measured along the axis of otolith growth revealed that almost half of the juveniles had moved at least some distance from their natal streams. Finally, otolith Sr profiles from three spawning adults confirmed homing to natal streams and use of nonoverlapping habitats over their migratory lifetimes. Our study demonstrates that otolith geochemistry records movements of cutthroat trout through Sr isoscapes and therefore provides a method that complements and extends the utility of conventional tagging techniques in understanding life history strategies and conservation needs of freshwater fishes in river networks.

  9. 5-Hydroxytryptamine-induced calcium-channel gating in rainbow trout (Oncorhynchus mykiss) peripheral blood lymphocytes.

    PubMed Central

    Ferriere, F; Khan, N A; Meyniel, J P; Deschaux, P

    1997-01-01

    The present study was conducted on peripheral blood lympho-cytes of rainbow trout (Oncorhynchus mykiss) to assess the role of 5-hydroxytryptamine (5-HT; 'serotonin') in calcium signalling. 5-HT-induced increases in intracellular free calcium concentrations, [Ca2+]i, and its action was mediated by 5-HT receptor subtype 3 (5-HT3), but not by 5-HT receptor subtype 1A (5-HT1A) or subtype 2 (5-HT2) in these cells. In Ca2+-containing medium (1 mM CaCl2), 5-HT and 2-methyl-5-HT (5-HT3 receptor agonist) induced increases in [Ca2+]i, whereas in Ca2+-free medium (0 Ca2+, 1 mM EGTA), these two agents failed to evoke increases in [Ca2+]i in these cells, demonstrating that 5-HT mobilizes Ca2+ from the extracellular environment. Furthermore, 5-HT-induced increases in [Ca2+]i are not contributed to by the intracellular endoplasmic reticulum (ER) pool, as thapsigargin, an agent that recruits Ca2+ from ER stores, had additive effects on 5-HT-induced [Ca2+]i responses in fish peripheral lymphocytes. 5-HT-induced increases in [Ca2+]i were mediated by 5-HT3 receptors via gating the calcium through L-type, but not N-type, calcium channels in trout lymphocytes. PMID:9173890

  10. Development and pharmacokinetic evaluation of erythromycin lipidic formulations for oral administration in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Serdoz, Francesca; Voinovich, Dario; Perissutti, Beatrice; Grabnar, Iztok; Hasa, Dritan; Ballestrazzi, Rodolfo; Coni, Ettore; Pellegrini, Enrico

    2011-08-01

    The aim of this work was to enhance the bioavailability of erythromycin base when administered orally in rainbow trout (Oncorhynchus mykiss). Since erythromycin is normally given in the form of medicated feed, in this study three new types of feed formulation were developed. A self-emulsifying system and two types of double microemulsions (O/W/O) were prepared, characterized and adsorbed on a commercial extruded diet for fish. The emulsified systems were based on saturated polyglycolized glycerides and mono- and diglycerides of medium-chain fatty acids (as oily phase), Tween 80 (as surfactant) and, in the case of double microemulsions, distilled water. The systems differed in percentage composition and for the amount and position of erythromycin in different phases. The three medicated feed were then administered orally by means of a gastric probe to rainbow trout and their relative bioavailability was estimated in comparison with that obtained after oral administration of feed with erythromycin powder. For each medicated feed, 80 fish were tested. Finally, plasma profiles of erythromycin after single administration of medicated feeds were used to predict profiles obtainable by administering once-daily medicated feeds for 7 consecutive days. The results proved that the feeds containing microemulsified erythromycin provided largely superior oral bioavailability and the advantage of obtaining the same efficacy against bacterial infections with a much lower dose of drug. PMID:21402156

  11. Acute effects of chlorinated resin acid exposure on juvenile rainbow trout, Oncorhynchus mykiss

    SciTech Connect

    Kennedy, C.J.; Sweeting, R.M.; Farrell, A.P.; McKeown, B.A.; Johansen, J.A.

    1995-06-01

    The effects of an acute exposure to either 14-monochlorodehydroabietic acid (MCDHAA) or 12,14-dichlorodehydroabietic acid (DCDHAA) were examined in juvenile rainbow trout, Oncorhynchus mykiss. The experimentally determined 96-h LC50 values (and their 95% confidence limits) were 1.03 (0.72, 1.48) and 0.91 (0.70, 1.21) mg/L, for MCDHAA and DCDHAA, respectively. To measure effects on several biochemical parameters, swimming performance, and disease resistance, juvenile trout were exposed for 24 h to sublethal concentrations of one or the other resin acid in an intermittent-flow respirometer. Hematocrit, plasma lactate, and liver protein were significantly affected by exposure to the highest dose (80% of the 96-h LC50 value) of either of the resin acids. Plasma cortisol levels were 14- and 3-fold higher than were controls. Resistance to infection by Aeromonas salmonicida was significantly reduced; the cumulative percent mortalities due to furunculosis in fish exposed to MCDHAA or DCDHAA reached 20 and 26%, respectively. Swimming performance, measured as critical swimming speed (mean values 6.32 {+-} 0.20 and 5.93 {+-} 0.15 body lengths per second for MCDHAA and DCDHAA, respectively), was not significantly affected by resin acid exposure.

  12. An experimental vaccine against Aeromonas hydrophila can induce protection in rainbow trout, Oncorhynchus mykiss (Walbaum)

    USGS Publications Warehouse

    LaPatra, S.E.; Plant, K.P.; Alcorn, S.; Ostland, V.; Winton, J.

    2010-01-01

    A candidate vaccine against Aeromonas hydrophila in rainbow trout, Oncorhynchus mykiss, was developed using a bacterial lysate. To test the strength of protection, A. hydrophila challenge models were compared using injection into both the intraperitoneal (IP) cavity and the dorsal sinus (DS) with selected doses of live bacteria washed in saline or left untreated. Unlike the IP route, injection into the DS with either saline washed or unwashed cells resulted in consistent cumulative mortality and a dose response that could be used to establish a standard challenge having an LD50 of approximately 3 × 107 colony forming units per fish. Survivors of the challenge suffered significantly lower mortality upon re-challenge than naïve fish, suggesting a high level of acquired resistance was elicited by infection. Passive immunization using serum from hyper-immunized fish also resulted in significantly reduced mortality indicating protection can be transferred and that some portion of resistance may be antibody mediated. Vaccination of groups of rainbow trout with A. hydrophila lysate resulted in significant protection against a high challenge dose but only when injected along with Freund’s complete adjuvant. At a low challenge dose, mortality in all groups was low, but the bacterial lysate alone appeared to offer some protection.

  13. Identification, characterization and genetic mapping of TLR1 loci in rainbow trout (Oncorhynchus mykiss)

    USGS Publications Warehouse

    Palti, Y.; Rodriguez, M.F.; Gahr, S.A.; Purcell, M.K.; Rexroad, C. E., III; Wiens, G.D.

    2010-01-01

    Induction of innate immune pathways is critical for early anti-microbial defense but there is limited understanding of how teleosts recognize microbial molecules and activate these pathways. In mammals, Toll-like receptors (TLR) 1 and 2 form a heterodimer involved in recognizing peptidoglycans and lipoproteins of microbial origin. Herein, we identify and describe the rainbow trout (Oncorhynchus mykiss) TLR1 gene ortholog and its mRNA expression. Two TLR1 loci were identified from a rainbow trout bacterial artificial chromosome (BAC) library using DNA sequencing and genetic linkage analyses. Full length cDNA clone and direct sequencing of four BACs revealed an intact omTLR1 open reading frame (ORF) located on chromosome 14 and a second locus on chromosome 25 that contains a TLR1 pseudogene. The duplicated trout loci exhibit conserved synteny with other fish genomes that extends beyond the TLR1 gene sequences. The omTLR1 gene includes a single large coding exon similar to all other described TLR1 genes, but unlike other teleosts it also has a 5??? UTR exon and intron preceding the large coding exon. The omTLR1 ORF is predicted to encode an 808 amino-acid protein with 69% similarity to the Fugu TLR1 and a conserved pattern of predicted leucine-rich repeats (LRR). Phylogenetic analysis grouped omTLR1 with other fish TLR1 genes on a separate branch from the avian TLR1 and mammalian TLR1, 6 and 10. omTLR1 expression levels in rainbow trout anterior kidney leukocytes were not affected by the human TLR2/6 and TLR2/1 agonists diacylated lipoprotein (Pam2CSK4) and triacylated lipoprotein (Pam3CSK4). However, due to the lack of TLR6 and 10 genes in teleost genomes and up-regulation of TLR1 mRNA in response to LPS and bacterial infection in other fish species we hypothesize an important role for omTLR1 in anti-microbial immunity. Therefore, the identification of a TLR2 ortholog in rainbow trout and the development of assays to measure ligand binding and downstream signaling

  14. Identification, characterization and genetic mapping of TLR1 loci in rainbow trout (Oncorhynchus mykiss)

    USGS Publications Warehouse

    Palti, Yniv; Rodriguez, M. Fernanda; Gahr, Scott A.; Purcell, Maureen K.; Rexroad, Caird E., III; Wiens, Gregory D.

    2010-01-01

    Induction of innate immune pathways is critical for early anti-microbial defense but there is limited understanding of how teleosts recognize microbial molecules and activate these pathways. In mammals, Toll-like receptors (TLR) 1 and 2 form a heterodimer involved in recognizing peptidoglycans and lipoproteins of microbial origin. Herein, we identify and describe the rainbow trout (Oncorhynchus mykiss) TLR1 gene ortholog and its mRNA expression. Two TLR1 loci were identified from a rainbow trout bacterial artificial chromosome (BAC) library using DNA sequencing and genetic linkage analyses. Full length cDNA clone and direct sequencing of four BACs revealed an intact omTLR1 open reading frame (ORF) located on chromosome 14 and a second locus on chromosome 25 that contains a TLR1 pseudogene. The duplicated trout loci exhibit conserved synteny with other fish genomes that extends beyond the TLR1 gene sequences. The omTLR1 gene includes a single large coding exon similar to all other described TLR1 genes, but unlike other teleosts it also has a 5' UTR exon and intron preceding the large coding exon. The omTLR1 ORF is predicted to encode an 808 amino-acid protein with 69% similarity to the Fugu TLR1 and a conserved pattern of predicted leucine-rich repeats (LRR). Phylogenetic analysis grouped omTLR1 with other fish TLR1 genes on a separate branch from the avian TLR1 and mammalian TLR1, 6 and 10. omTLR1 expression levels in rainbow trout anterior kidney leukocytes were not affected by the human TLR2/6 and TLR2/1 agonists diacylated lipoprotein (Pam2CSK4) and triacylated lipoprotein (Pam3CSK4). However, due to the lack of TLR6 and 10 genes in teleost genomes and up-regulation of TLR1 mRNA in response to LPS and bacterial infection in other fish species we hypothesize an important role for omTLR1 in anti-microbial immunity. Therefore, the identification of a TLR2 ortholog in rainbow trout and the development of assays to measure ligand binding and downstream signaling are

  15. Intersex occurrence in rainbow trout (Oncorhynchus mykiss) male fry chronically exposed to ethynylestradiol.

    PubMed

    Depiereux, Sophie; Liagre, Mélanie; Danis, Lorraine; De Meulder, Bertrand; Depiereux, Eric; Segner, Helmut; Kestemont, Patrick

    2014-01-01

    This study aimed to investigate the male-to-female morphological and physiological transdifferentiation process in rainbow trout (Oncorhynchus mykiss) exposed to exogenous estrogens. The first objective was to elucidate whether trout develop intersex gonads under exposure to low levels of estrogen. To this end, the gonads of an all-male population of fry exposed chronically (from 60 to 136 days post fertilization--dpf) to several doses (from environmentally relevant 0.01 µg/L to supra-environmental levels: 0.1, 1 and 10 µg/L) of the potent synthetic estrogen ethynylestradiol (EE2) were examined histologically. The morphological evaluations were underpinned by the analysis of gonad steroid (testosterone, estradiol and 11-ketotestosterone) levels and of brain and gonad gene expression, including estrogen-responsive genes and genes involved in sex differentiation in (gonads: cyp19a1a, ER isoforms, vtg, dmrt1, sox9a2; sdY; cyp11b; brain: cyp19a1b, ER isoforms). Intersex gonads were observed from the first concentration used (0.01 µg EE2/L) and sexual inversion could be detected from 0.1 µg EE2/L. This was accompanied by a linear decrease in 11-KT levels, whereas no effect on E2 and T levels was observed. Q-PCR results from the gonads showed downregulation of testicular markers (dmrt1, sox9a2; sdY; cyp11b) with increasing EE2 exposure concentrations, and upregulation of the female vtg gene. No evidence was found for a direct involvement of aromatase in the sex conversion process. The results from this study provide evidence that gonads of male trout respond to estrogen exposure by intersex formation and, with increasing concentration, by morphological and physiological conversion to phenotypic ovaries. However, supra-environmental estrogen concentrations are needed to induce these changes. PMID:25033040

  16. Characterization of three novel beta-defensin antimicrobial peptides in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Casadei, Elisa; Wang, Tiehui; Zou, Jun; González Vecino, Jose L; Wadsworth, Simon; Secombes, Christopher J

    2009-10-01

    An initial bioinformatics investigation followed by cloning and sequencing analysis, has led to the identification of three novel members (omDB-2, omDB-3, omBD-4) of the beta-defensin family in rainbow trout (Oncorhynchus mykiss). The contiguous sequences could be translated to give predicted peptides of 62 (omDB-2), 63 (omDB-3) and 68 (omDB-4) amino acids (aa) in length, with mature peptides of 43 (omDB-2), 39 (omDB-3) and 42 (omDB-4) aa, with no obvious proregion present. Analysis of the gene organization found that all three new genes contained three exons divided by two introns, as seen in defensin genes of other fish species. Constitutive expression of all the trout defensins was detected by RT-PCR in a wide range of mucosal and systemic tissues from healthy fish, with omDB-3 and omDB-4 showing the highest expression levels. Following bacterial challenge in vivo, the defensin genes were induced at the three mucosal sites examined (skin, gill, gut), with levels of omDB-2 and omDB-3 increased some 16-fold in gut and gill respectively. Using polyinosinic polycytosinic RNA (polyI:C) as a viral mimic, all of the four trout beta-defensin genes were induced in head kidney primary leucocyte cultures at 4h post-stimulation, with omDB-1 and omDB-3 particularly highly expressed. These data suggest that beta-defensins are likely an important component of the innate defences of fish, and reveal an added level of antimicrobial peptide complexity in fish to that known previously. PMID:19709750

  17. Nutritional regulation of long-chain PUFA biosynthetic genes in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Gregory, Melissa K; Collins, Robert O; Tocher, Douglas R; James, Michael J; Turchini, Giovanni M

    2016-05-28

    Most studies on dietary vegetable oil in rainbow trout (Oncorhynchus mykiss) have been conducted on a background of dietary EPA (20 : 5n-3) and DHA (22 : 6n-3) contained in the fishmeal used as a protein source in aquaculture feed. If dietary EPA and DHA repress their endogenous synthesis from α-linolenic acid (ALA, 18 : 3n-3), then the potential of ALA-containing vegetable oils to maintain tissue EPA and DHA has been underestimated. We examined the effect of individual dietary n-3 PUFA on the expression of the biosynthetic genes required for metabolism of ALA to DHA in rainbow trout. A total of 720 juvenile rainbow trout were allocated to twenty-four experimental tanks and assigned one of eight diets. The effect of dietary ALA, EPA or DHA, in isolation or in combination, on hepatic expression of fatty acyl desaturase (FADS)2a(Δ6), FADS2b(Δ5), elongation of very long-chain fatty acid (ELOVL)5 and ELOVL2 was examined after 3 weeks of dietary intervention. The effect of these diets on liver and muscle phospholipid PUFA composition was also examined. The expression levels of FADS2a(Δ6), ELOVL5 and ELOVL2 were highest when diets were high in ALA, with no added EPA or DHA. Under these conditions ALA was readily converted to tissue DHA. Dietary DHA had the largest and most consistent effect in down-regulating the gene expression of all four genes. The ELOVL5 expression was the least responsive of the four genes to dietary n-3 PUFA changes. These findings should be considered when optimising aquaculture feeds containing vegetable oils and/or fish oil or fishmeal to achieve maximum DHA synthesis. PMID:26987422

  18. Trace classical conditioning in rainbow trout (Oncorhynchus mykiss): what do they learn?

    PubMed

    Nordgreen, Janicke; Janczak, Andrew Michael; Hovland, Anne Lene; Ranheim, Birgit; Horsberg, Tor Einar

    2010-03-01

    There are two main memory systems: declarative and procedural memory. Knowledge of these two systems in fish is scarce, and controlled laboratory studies are needed. Trace classical conditioning is an experimentally tractable model of declarative memory. We tested whether rainbow trout (Oncorhynchus mykiss) can learn by trace conditioning and form stimulus-stimulus, as opposed to stimulus-response, associations. We predicted that rainbow trout trained by trace conditioning would show appetitive behaviour (conditioned response; CR) towards the conditioned stimulus (CS; light), and that the CR would be sensitive to devaluation of the unconditioned stimulus (US; food). The learning group (L, N = 14) was trained on a CS + US contingency schedule with a trace interval of 3.4 s. The control group (CtrL, N = 4) was kept on a completely random schedule. The fish that learnt were further trained as either an experimental (L, N = 6) or a memory control (CtrM, N = 3) group. The L group had the US devalued. The CtrM group received only food. No fish in the CtrL group, but nine fish from the L group conditioned to the light. When tested, five L fish changed their CRs after US devaluation, indicating learning by stimulus-stimulus association of the light with the food. CtrM fish retained their original CRs. To the best of our knowledge, this experiment is the first to show that rainbow trout can learn by trace classical conditioning. The results indicate that the fish learnt by 'facts-learning' rather than by reflex acquisition in this study. PMID:19657682

  19. Imprinting Salmon and Steelhead Trout for Homing, 1983 Annual Report of Research.

    SciTech Connect

    Slatick, Emil

    1984-09-01

    The National Marine Fisheries Service (NMFS), under contract to the Bonneville Power Administration, began conducting research on imprinting Pacific salmon and steelhead for homing in 1978. In the juvenile marking phase, over 4 million juvenile salmon and steelhead were marked and released in 23 experiments. The primary objectives were to determine a triggering mechanism to activate the homing imprint, if a single imprint or a sequential imprint is necessary to assure homing, and the relationship between the physiological condition of fish and their ability to imprint. Ten experimental studies are discussed. Six of the studies employed a variety of techniques for imprinting fish. The remaining four tested the feasibility of imprinting fish by a short-distance voluntary migration before transport. In five experiments, survival was enhanced by the imprint-transportation procedures, and homing to the homing site area was partly successful. Returns from the Astoria, Oregon, release of fall chinook salmon from Big Creek Hatchery (Knappa, Oregon), for example, showed that limited short distance migration imprinting should provide 2-3 time more fish to the various fisheries while providing adequate returns to the hatchery for egg take each year. 21 refs., 12 figs, 12 tabs.

  20. Evaluation of Fishway Designs for Downstream Passage of Spring Chinook Salmon and Steelhead Trout Smolts, 1987 Final Report.

    SciTech Connect

    Congleton, J.L.; Wagner, E.J.; Ringe, R.R.

    1988-03-01

    The stress response of chinook salmon and steelhead trout smolts to passage through three different flumes was tested by assaying plasma cortisol concentrations before and after flume passage. In addition, descaling of fish was recorded before and after flume passage, and the ability of the flumes to pass adult chinook salmon and debris was determined. The three flumes were a corrugated metal flume (CMF), a 4- foot wide baffled flume (BF4), and a 2-foot wide baffled flume (BF2). Each flume was tested under conditions: 1) at night, 2) during the day with a perforated metal cover, which reduced the amount of light entering the flume by about half (partially darkened), and 3) during the day with the perforated cover and additional double layer of black plastic (completely darkened). Plasma cortisol concentrations were not significantly elevated in chinook salmon smolts after passage through any of the flumes (P>0.2, ANOVA). In daytime tests of partially and completely darkened flumes cortisol concentrations were consistently decreased following flume passage. We attribute this to pre-test stress (holding of fish in small tanks) and to the absence of a strong stress response to flume passage. Flume design did not have a significant effect on cortisol concentrations (P=0.9).Total darkening of the flumes during daytime was beneficial: cortisol concentrations were lower (P=0.03) in chinook salmon smolts passing through completely darkened flumes than in smolts passing through partially darkened flumes. 16 refs., 15 figs.

  1. A novel member of the family Hepeviridae from cutthroat trout (Oncorhynchus clarkii)

    USGS Publications Warehouse

    Batts, William; Yun, Susan; Hedrick, Ronald; Winton, James

    2011-01-01

    Beginning in 1988, the Chinook salmon embryo (CHSE-214) cell line was used to isolate a novel virus from spawning adult trout in the state of California, USA. Termed the cutthroat trout (Oncorhynchus clarkii) virus (CTV), the small, round virus was not associated with disease, but was subsequently found to be present in an increasing number of trout populations in the western USA, likely by a combination of improved surveillance activities and the shipment of infected eggs to new locations. Here, we report that the full length genome of the 1988 Heenan Lake isolate of CTV consisted of 7269 nucleotides of positive-sense, single-stranded RNA beginning with a 5' untranslated region (UTR), followed by three open reading frames (ORFs), a 3' UTR and ending in a polyA tail. The genome of CTV was similar in size and organization to that of Hepatitis E virus (HEV) with which it shared the highest nucleotide and amino acid sequence identities. Similar to the genomes of human, rodent or avian hepeviruses, ORF 1 encoded a large, non-structural polyprotein that included conserved methyltransferase, protease, helicase and polymerase domains, while ORF 2 encoded the structural capsid protein and ORF 3 the phosphoprotein. Together, our data indicated that CTV was clearly a member of the family Hepeviridae, although the level of amino acid sequence identity with the ORFs of mammalian or avian hepeviruses (13-27%) may be sufficiently low to warrant the creation of a novel genus. We also performed a phylogenetic analysis using a 262. nt region within ORF 1 for 63 isolates of CTV obtained from seven species of trout reared in various geographic locations in the western USA. While the sequences fell into two genetic clades, the overall nucleotide diversity was low (less than 8.4%) and many isolates differed by only 1-2 nucleotides, suggesting an epidemiological link. Finally, we showed that CTV was able to form persistently infected cultures of the CHSE-214 cell line that may have use

  2. Dermal absorption of three waterborne chloroethanes in rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus).

    PubMed

    McKim, J M; Nichols, J W; Lien, G J; Hoffman, A D; Gallinat, C A; Stokes, G N

    1996-06-01

    In vivo estimates of xenobiotic chemical flux across the dermal surface of intact fish were obtained by measuring chemical loss from venous blood to expired water. An experimental system was developed to separate the dermal route of exposure from all other routes. The system was then used to measure dermal absorption of tetrachloroethane (TCE), pentachloroethane (PCE), and hexachloroethane (HCE) in channel catfish (Ictalurus punctatus) and rainbow trout (Oncorhynchus mykiss), two fish with very different skin anatomies. The kinetics of accumulation varied among chemicals, but for each compound were similar among species. TCE accumulated rapidly, reaching steady state in blood within 48 hr. Steady state was not reached in 48 hr with PCE or HCE, although blood levels of PCE were probably close to steady-state values. Dermal flux estimates (based on branchial efflux) for TCE, PCE, and HCE were two to four times greater in catfish than in trout. Arterial blood concentrations of each compound were three to six times greater in catfish. These observations are indicative of greater flux across catfish skin, augmented by higher blood:water chemical partitioning. Trout skin is covered with scales and has no taste buds, while catfish skin does not possess scales and has numerous taste bud papillae. Both scales and taste bud papillae originate in the dermis and extend to the skin surface through the epidermis. In catfish these taste buds may offer channels through which chemicals diffuse across the epidermis to the more vascularized dermis. A comparison of dermal and branchial uptake was made by estimating zero-time dermal and branchial fluxes for all three chloroethanes. The mean dermal fluxes for TCE, PCE, and HCE ranged from 1.4 to 2.8, 1.8 to 3.6, and 1.4 to 3.2% of the total flux (branchial plus dermal) in rainbow trout and channel catfish, respectively. This research demonstrates that dermal absorption of waterborne chemicals occurs in large adult fish and results in

  3. Effects of acid rock drainage on stocked rainbow trout (Oncorhynchus mykiss): an in-situ, caged fish experiment.

    PubMed

    Todd, Andrew S; McKnight, Diane M; Jaros, Chris L; Marchitto, Thomas M

    2007-07-01

    In-situ caged rainbow trout (Oncorhynchus mykiss) studies reveal significant fish toxicity and fish stress in a river impacted by headwater acid rock drainage (ARD). Stocked trout survival and aqueous water chemistry were monitored for 10 days at 3 study sites in the Snake River watershed, Colorado, U.S.A. Trout mortality was positively correlated with concentrations of metals calculated to be approaching or exceeding conservative toxicity thresholds (Zn, Mn, Cu, Cd). Significant metal accumulation on the gills of fish stocked at ARD impacted study sites support an association between elevated metals and fish mortality. Observations of feeding behavior and significant differences in fish relative weights between study site and feeding treatment indicate feeding and metals-related fish stress. Together, these results demonstrate the utility of in-situ exposure studies for stream stakeholders in quantifying the relative role of aqueous contaminant exposures in limiting stocked fish survival. PMID:17180429

  4. Biotransformation of pentachlorophenol, aniline and biphenyl in isolated rainbow trout (Oncorhynchus mykiss) hepatocytes: comparison with in vivo metabolism.

    PubMed

    Cravedi, J P; Lafuente, A; Baradat, M; Hillenweck, A; Perdu-Durand, E

    1999-05-01

    1. The biotransformation of pentachlorophenol (PCP), aniline and biphenyl in rainbow trout (Oncorhynchus mykiss) isolated liver cells was investigated to examine if fish hepatocytes represent a suitable alternative to the in vivo approach for studying the biotransformation of chemicals. Each compound was incubated at two concentrations (10 and 60 microM) for 2 h. For comparison, the metabolic profile of these xenobiotics was also studied in urine and bile of trout orally exposed to 1.8-4.0 mg/kg wet wt of each compound. 2. In vitro as in vivo, PCP glucuronide and to a lesser extent PCP sulphate were the metabolites formed by trout from PCP. 3. Aniline was mainly metabolized to acetanilide and to a lesser extent to 2-aminophenol by isolated hepatocytes, but neither hydroxylated acetanilide nor conjugates were found in vitro whereas they were present in bile and urine of trout treated with this chemical. 4. Trout hepatocytes metabolized biphenyl to hydroxylated and dihydroxylated products and the corresponding glucuronides. These results correlated well with the metabolic profile obtained from the bile of trout exposed to this pesticide. 5. It is concluded that although hepatocytes are well suited for several types of biotransformation studies, the fact that this system may in some cases produce a different metabolic pattern than in vivo should be considered when attempting to extrapolate in vitro to in vivo data. PMID:10379987

  5. Differences in neurobehavioral responses of chinook salmon (Oncorhynchus tshawytscha) and rainbow trout (Oncorhynchus mykiss) exposed to copper and cobalt: Behavioral avoidance

    SciTech Connect

    Hansen, J.A.; Marr, J.C.A.; Lipton, J.; Cacela, D.; Bergman, H.L.

    1999-09-01

    Behavioral avoidance of copper (Cu), cobalt (Co), and a Cu and Co mixture in soft water differed greatly between rainbow trout (Oncorhynchus mykiss) and chinook salmon (O. tshawytscha). Chinook salmon avoided at least 0.7 {micro}g Cu/L, 24 {micro}g Co/L, and the mixture of 1.0 {micro}g Cu/L and 0.9 {micro}g Co/L, whereas rainbow trout avoided at least 1.6 {micro}g Cu/L, 180 {micro}g Co/L, and the mixture of 2.6 {micro}g Cu/L and 2.4 {micro}g Co/L. Chinook salmon were also more sensitive to the toxic effects of Cu in that they failed to avoid {ge}44 {micro}g Cu/L, whereas rainbow trout failed to avoid {ge}180 {micro}g Cu/L. Furthermore, following acclimation to 2 {micro}g Cu/L, rainbow trout avoided 4 {micro}g Cu/L and preferred clean water, but chinook salmon failed to avoid any Cu concentrations and did not prefer clean water. The failure to avoid high concentrations of metals by both species suggests that the sensory mechanism responsible for avoidance responses was impaired. Exposure to Cu concentrations that were not avoided could result in lethality from prolonged Cu exposure or in impairment of sensory-dependent behaviors that are essential for survival and reproduction.

  6. Angler harvest, hatchery return, and tributary stray rates of recycled adult summer steelhead Oncorhynchus mykiss in the Cowlitz River, Washington

    USGS Publications Warehouse

    Kock, Tobias J.; Perry, Russell W.; Gleizes, Chris; Dammers, Wolf; Liedtke, Theresa L.

    2016-01-01

    Hatchery ‘recycling’ programs have been used to increase angling opportunities by re-releasing fish into a river after they returned to a hatchery or fish trap. Recycling is intended to increase opportunities for fishermen, but this strategy could affect wild fish populations if some recycled fish remain in the river and interact with wild fish populations. To quantify hatchery return and angler harvest rates of recycled steelhead, we conducted a 2-year study on the Cowlitz River, Washington. A total of 1051 steelhead were recycled, including 218 fish that were radio-tagged. Fates of recycled steelhead were similar between years: 48.4% returned to the hatchery, 19.2% were reported captured by anglers, and 32.4% remained in the river. A multistate model quantified the effects of covariates on hatchery return and angler harvest rates, which were positively affected by river discharge and negatively affected by time since release. However, hatchery return rates increased and angler harvest rates decreased during periods of increasing discharge. A total of 21.1% (46 fish) of the radio-tagged steelhead failed to return to the hatchery or be reported by anglers, but nearly half of those fish (20 fish) appeared to be harvested and not reported. The remaining tagged fish (11.9% of the radio-tagged population) were monitored into the spawning period, but only five fish (2.3% of the radio-tagged population) entered tributaries where wild steelhead spawning occurs. Future research focused on straying behaviour, and spawning success of recycled steelhead may further advance the understanding of the effects of recycling as a management strategy.

  7. Migration depths of adult steelhead Oncorhynchus mykiss in relation to dissolved gas supersaturation in a regulated river system

    SciTech Connect

    Johnson, Eric L.; Clabough, Tami S.; Caudill, Christopher C.; keefer, matthew L.; Peery, Christopher A.; Richmond, Marshall C.

    2010-04-01

    Adult steelhead tagged with archival transmitters primarily migrated through a large river corridor at depths > 2 m, interspersed with frequent but short (< 5 min) periods closer to the surface. The recorded swimming depths and behaviours probably provided adequate hydrostatic compensation for the encountered supersaturated dissolved gas conditions and probably limited development of gas bubble disease (GBD). Results parallel those from a concurrent adult Chinook salmon study, except steelhead experienced greater seasonal variability and were more likely to have depth-uncompensated supersaturation exposure in some dam tailraces, perhaps explaining the higher incidence of GBD in this species.

  8. The orexinergic system in rainbow trout Oncorhynchus mykiss and its regulation by dietary lipids.

    PubMed

    Varricchio, Ettore; Russo, Finizia; Coccia, Elena; Turchini, Giovanni Mario; Francis, David Scott; Paolucci, Marina

    2015-08-01

    In this study, we report the distribution of orexin A (OXA), orexin B (OXB), and orexin receptor (OX2R) immunoreactive (ir) cells in the hypothalamus and gastrointestinal tract of Oncorhynchus mykiss fed diets with different dietary fatty acid compositions. Trout were fed five iso-energetic experimental diets containing fish oil, or one of four different vegetable oils (olive, sunflower, linseed, and palm oils) as the added dietary lipid source for 12 weeks. OXA, OXB, and OX2R immunoreactive neurons and nervous fibers were identified in the lateral and ventro-medial hypothalamus. OXA, OXB, and OX2R ir cells were found in the mucosa and glands of the stomach and in the mucosa of both the pyloric cecae and intestine. OX2R ir cells were localized in the mucosa layer of both the pyloric cecae and intestine. These immunohistochemical (IHC) results were confirmed via Western blotting. Antibodies against preproorexin (PPO) crossreacted with a band of ∼16 kDa in the hypothalamus, stomach, pyloric cecae, and intestine. Antibodies against OX2R crossreacted with a band of ∼38 kDa in the hypothalamus, pyloric cecae, and intestine. The presence and distribution of OXA, OXB, and OX2R ir cells in the hypothalamus and gastrointestinal tract did not appear to be affected by dietary oils. The presence of orexin system immunoreactive cells in the stomach, pyloric cecae, and intestine of rainbow trout, but not in the enteric nervous system, could suggest a possible role of these peptides as signaling of gastric emptying or endocrine modulation, implying a main local action played by orexins. PMID:26096763

  9. Induction of vitellogenesis in 17alpha-ethinylestradiol-exposed rainbow trout (Oncorhynchus mykiss): a method comparison.

    PubMed

    Verslycke, Tim; Vandenbergh, Gert F; Versonnen, Bram; Arijs, Katrien; Janssen, Colin R

    2002-08-01

    Juvenile rainbow trout, Oncorhynchus mykiss, were exposed to the synthetic estrogen 17alpha-ethinylestradiol (EE(2)) through injection (1, 10, 25 and 50 microg EE(2)/g fish/week) and via water exposure (1, 10 and 100 ng EE(2)/l). After seven (injection and water exposure) and 14 days (only for water exposure), blood and plasma vitellogenin concentrations were quantified using indirect endpoints, i.e. plasma alkaline-labile phosphorus (ALP), plasma protein and plasma calcium. In addition, the relative gonad (GSI) and liver weight (HSI) were recorded. Actual plasma vitellogenin concentrations were measured with an enzyme immunoassay. Only fish injected with 50 microg EE(2)/g fish had a significantly higher gonad weight. No concentration-dependent changes in the HSI were detected in fish exposed via the water, but a significant dose-dependent increase of the HSI was observed in fish injected with EE(2). Exposure of rainbow trout to EE(2) had a significant effect on all tested plasma parameters. Plasma protein, phosphoprotein and calcium concentrations were significantly higher after two weeks exposure to 100 ng EE(2)/l. Fish injected with 10, 25 and 50 microg EE(2)/g fish exhibited increased plasma protein concentrations after 1 week. Compared to the controls, plasma ALP and calcium levels were significantly higher in all injected fish. A significant and positive correlation was observed between all three plasma parameters and between these indirect parameters and the actual plasma vitellogenin concentrations. These findings indicate that both the plasma ALP and the plasma calcium assay have a similar sensitivity as that of available antibody-based assays (EIA), at least in EE(2) exposure studies, and thus these assays can provide a rapid, simple and cost-effective alternative to available immunoassays. PMID:12223204

  10. Chronic toxicity of 14 phthalate esters to Daphnia magna and rainbow trout (Oncorhynchus mykiss)

    SciTech Connect

    Rhodes, J.E.; Adams, W.J.; Biddinger, G.R.; Robillard, K.A.; Gorsuch, J.W.

    1995-11-01

    Chronic toxicity studies were performed with commercial phthalate esters and Daphnia magna (14 phthalates) and rainbow trout (Oncorhynchus mykiss) (six phthalates). For the lower-molecular-weight phthalate esters--dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and butylbenzyl phthalate (BBP)--the results of the studies indicated a general trend in which toxicity for both species increased as water solubility decreased. The geometric mean maximum acceptable toxicant concentration(GM-MATC) for D. magna ranged from 0.63 to 34.8 mg/L. For the higher-molecular-weight phthalate esters--dihexyl phthalate (DHP), butyl 2-ethylhexyl phthalate (BOP), di-(n-hexyl, n-octyl, n-decyl) phthalate (610P), di-(2-ethylhexyl) phthalate (DEHP), diisooctyl phthalate (DIOP), diisononyl phthalate (DINP), di-(heptyl, nonyl, undecyl) phthalate (711P), diisodecyl phthalate (DIDP), diundecyl phthalate (DUP), and ditridecyl phthalate (DTDP)--the GM-MATC values ranged from 0.042 to 0.15 mg/L. Survival was equally sensitive and sometimes more sensitive than reproduction. The observed toxicity to daphnids with most of the higher-molecular-weight phthalate esters appeared to be due to surface entrapment or a mode of toxicity that is not due to exposure to dissolved aqueous-phase chemical. Early life-stage toxicity studies with rainbow trout indicated that survival (DMP) and growth (DBP) were affected at 24 and 0.19 mg/L, respectively. This pattern of observed toxicity with the lower-molecular-weight phthalate esters and not the higher-molecular-weight phthalate esters is consistent with previously reported acute toxicity studies for several aquatic species.

  11. The effects of soft-water acclimation on gill structure in the rainbow trout Oncorhynchus mykiss.

    PubMed

    Greco, A M; Fenwick, J C; Perry, S F

    1996-07-01

    Rainbow trout (Oncorhynchus mykiss) were exposed to ion-poor (soft) water to test the hypothesis that naturally induced proliferation of branchial chloride cells causes a thickening of the blood-to-water diffusion barrier. This was achieved by using a combination of scanning and transmission electron-microscopic techniques. Fish were exposed to soft-water conditions ([Na+]= 0.055 mmol l-1, [Cl-] approximately 0.029 mmol 1(-1), [Ca2+] approximately 0.059 mmol 1(-1), and [K+] approximately 0.007 mmol 1(-1)) for 1, 2, and 4 weeks. Marked chloride cell proliferation was evident at all sampling times with an approximate doubling of the gill epithelial surface area covered by chloride cells exposed to the water ("chloride cell fractional area"). The increases in chloride cell fractional area resulted from both increased numbers of cells and expanded apical surfaces of exposed individual cells. As a result of chloride cell proliferation, soft-water exposure was associated with a doubling of the lamellar blood-to-water diffusion distance from 3.26+/-0.08 microM to 6.58+/-0.43 microM as determined from transmission electron micrographs. These data demonstrated a positive correlation between chloride cell fractional area and blood-to-water diffusion distance. We conclude that, in trout, chloride cell proliferation during soft-water exposure, while presumably benefiting ionic regulation, may impair gas transfer owing to the associated thickening of the blood-to-water diffusion barrier. PMID:8766860

  12. Changes in Habitat and Populations of Steelhead Trout, Coho Salmon, and Chinook Salmon in Fish Creek, Oregon; Habitat Improvement, 1983-1987 Final Report.

    SciTech Connect

    Everest, Fred H.; Hohler, David B.; Cain, Thomas C.

    1988-03-01

    Construction and evaluation of salmonid habitat improvements on Fish Creek, a tributary of the upper Clackamas River, began in 1982 as a cooperative venture between the Estacada Ranger District, Mt. Hood National Forest, and the Anadromous Fish Habitat Research Unit of the Pacific Northwest Research Station (PNW), USDA Forest Service. The project was initially conceived as a 5-year effort (1982-1987) to be financed with Forest Service funds. The habitat improvement program and the evaluation of improvements were both expanded in mid-1983 when the Bonneville Power Administration (BPA) entered into an agreement with the Mt. Hood National Forest to cooperatively fund work on Fish Creek. Habitat improvement work in the basin is guided by the Fish Creek Habitat Rehabilitation-Enhancement Framework developed cooperatively by the Estacada Ranger District, the Oregon Department of Fish and Wildlife, and the Pacific Northwest Research Station. The framework examines potential factors limiting production of salmonids in the basin, and the appropriate habitat improvement measures needed to address the limiting factors. Habitat improvement work in the basin has been designed to: (1) improve quantity, quality, and distribution of spawning habitat for coho and spring chinook salmon and steelhead trout, (2) increase low flow rearing habitat for steelhead trout and coho salmon, (3) improve overwintering habitat for coho salmon and steelhead trout, (4) rehabilitate riparian vegetation to improve stream shading to benefit all species, and (5) evaluate improvement projects from a drainage wide perspective. The objectives of the evaluation include: (1) Drainage-wide evaluation and quantification of changes in salmonid spawning and rearing habitat resulting from a variety of habitat improvements. (2) Evaluation and quantification of changes in fish populations and biomass resulting from habitat improvements. (3) Benefit-cost analysis of habitat improvements.

  13. Microsatellite diversity in sympatric reproductive ecotypes of pacific steelhead (Oncorhynchus my kiss) from the Middle Fork Eel River, California

    USGS Publications Warehouse

    Nielsen, J.L.; Fountain, M.C.

    1999-01-01

    Genetic differentiation between two reproductive ecotypes of anadromous steelhead found in the Middle Fork Eel River in northern California was tested using 16 microsatellite loci. Twelve of these loci showed significant differences in allelic frequency between the two Middle Fork Eel River steelhead populations (Fisher's exact P<0.05). Fisher's combined test for independence also supported significant genetic separation between the two reproductive ecotype (P<0.001). Analysis of molecular variance indicated that only 1% of the overall microsatellite allelic variation contributed to differences between summer- and winter-run steelhead in the Middle Fork Eel River. Variation found among individuals within the two runs equaled 18.2%. Analyses showed less genetic distance between the two populations of steelhead in the Middle Fork Eel River than in comparisons made with geographically proximate coastal winter-run fish. Divergence time based on genetic distance for the two within-basin reproductive ecotypes was estimated to be 16,000-28,000 years ago. Copyright ?? Munksgaanl 1999.

  14. Rapid Diagnosis of IHN Virus Infection in Salmon and Steelhead Trout, Final Report.

    SciTech Connect

    Leong, JoAnn Ching

    1984-12-01

    The main objective for this study was the development of a rapid diagnostic method for IHN virus in fish tissue samples. The rationale for developing new techniques for diagnosing IHNV infection was that present methods were time consuming and dependent on virus neutralization by specific antisera, a reagent that was not readily available or reliable. Fish pathologists required a rapid detection method which was sensitive enough to detect virus strain differences so that they could provide data for effective management decisions in controlling the spread of IHNV. Bonneville Power Administration's (BPA) role in efforts in fish diseases and more generically the protection, mitigation, and enhancement of Columbia River salmon and steelhead populations, is mandated by Congress through the Pacific Northwest Electric Power Planning and Conservation Act (Regional Act), Pub. L. 96-501. Section 4 (h) of the Regional Act directs the Northwest Power Planning Council to develop a Fish and Wildlife Program. BPA's Administrator is authorized in Section 4 (h) (10) (A) to ''use funds and the authorities available to the extent affected by the development and operation of any hydroelectric project of the Columbia River and its tributaries''. The fund is to be used to implement measures that are consistent with the Council's Fish and Wildlife Program. The research detailed in this final report is consistent with these objectives. This final report has been prepared as part of BPA's policy to encourage the preservation and dissemination of research results by publication in scientific journals.

  15. Selection for upper thermal tolerance in rainbow trout (Oncorhynchus mykiss Walbaum).

    PubMed

    Chen, Zhongqi; Snow, Michael; Lawrence, Craig S; Church, Anthony R; Narum, Shawn R; Devlin, Robert H; Farrell, Anthony P

    2015-03-01

    Rainbow trout (Oncorhynchus mykiss Walbaum) in southern Western Australia have undergone passive selection for over 19 generations to survive high water temperatures. Based on the conceptual model of 'oxygen- and capacity-limited thermal tolerance', we measured critical thermal maximum (CTmax), maximum heart rate (fH,max) and aerobic scope to test the hypothesis that these rainbow trout can maintain aerobic scope at high temperatures through a robust cardiac performance supporting oxygen delivery. Across five family groups CTmax averaged 29.0±0.02°C. Aerobic scope was maximized at 15.8±0.3°C (Topt), while the upper pejus temperature (Tpej, set at 90% of maximum aerobic scope) was 19.9±0.3°C. Although aerobic scope decreased at temperatures above Topt, the value at 25°C remained well over 40% of the maximum. Furthermore, pharmacologically stimulated fH,max increased with temperature, reaching a peak value between 23.5±0.4 and 24.0±0.4°C (Tmax) for three family groups. The Arrhenius breakpoint temperature (TAB) for fH,max was 20.3±0.3 to 20.7±0.4°C, while the average Q10 breakpoint temperature (TQB, when the incremental Q10<1.6) for fH,max was 21.6±0.2 to 22.0±0.4°C. Collectively, fH,max progressively became less temperature dependent beyond 20°C (TAB and TQB), which coincides with the upper Tpej for aerobic scope. Although upper thermal performance indices for both aerobic scope and fH,max were compared among family groups in this population, appreciable differences were not evident. Compared with other populations of rainbow trout, the present assessment is consistent with the prediction that this strain has undergone selection and shows the ability to tolerate higher water temperatures. PMID:25573825

  16. Effect of dietary aloe vera on growth and lipid peroxidation indices in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Golestan, Ghazale; Salati, Amir Parviz; Keyvanshokooh, Saeed; Zakeri, Mohammad; Moradian, Hossein

    2015-01-01

    Aloe vera has been used worldwide in pharmaceutical, food and cosmetic industries due to the plethora of biological activities of its constituents. This study was done to evaluate the effects of dietary aloe vera on growth and lipid peroxidation in rainbow trout (Oncorhynchus mykiss). A total number of 480 O. mykiss (mean weight 9.50 ± 0.85 g) were randomized into four experimental groups including one control and three experimental groups that aloe vera was incorporated in their diet at 0.5, 1.0 and 2.0 g kg(-1). Trial was done for eight weeks. Then biometry and blood sampling were done. Plasma malondialdehyde, ferric reducing ability of plasma and growth index were estimated at the end of study. The results showed that aloe vera extract did not affect growth indices. Malondialdehyde was increased in the experimental group compared to the control group but ferric reducing ability of plasma showed a decrease in experimental groups (p < 0.05) compared to the control group. Our findings showed that dietary aloe vera have adverse effects on antioxidant defense system in O. mykiss. PMID:25992253

  17. Effects of Watercress (Nasturtium nasturtium) extract on selected immunological parameters of rainbow trout (Oncorhynchus mykiss)

    PubMed Central

    Asadi, M.S.; Mirvaghefei, A.R.; Nematollahi, M.A.; Banaee, M.; Ahmadi, K.

    2012-01-01

    Watercress (Nasturtium nasturtium) is a medical plant containing diverse chemically-active substances with biological properties. The present study was conducted to investigate the immunomodulatory effects of watercress extract on immunological and hematological parameters of rainbow trout (Oncorhynchus mykiss). Fish were fed for 21 days with diet supplemented with 0.1% and 1% of watercress extract per 1 kg food and with a normal diet as control. Hematological parameters such as red blood cells (RBC) and white blood cells (WBC), hematocrit (Hct), hemoglobin (Hb), RBC index like mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) as well as immunological parameters such as peroxidase, lysozyme and complement activities, total protein, albumin and globulin levels were measured after 21 days of watercress extract treatment. The results indicated that oral administration of 1 % watercress extract in fish may enhance some hematological and immunological parameters including Hb and MCHC, lysozyme and complement activities, total protein and globulin levels, compared to the controls after 21 days of experimental period. In conclusion, on the basis of these results, oral administration of watercress extract may be useful to improve fish’s immune system. PMID:26623289

  18. Effect of dietary aloe vera on growth and lipid peroxidation indices in rainbow trout (Oncorhynchus mykiss)

    PubMed Central

    Golestan, Ghazale; Salati, Amir Parviz; Keyvanshokooh, Saeed; Zakeri, Mohammad; Moradian, Hossein

    2015-01-01

    Aloe vera has been used worldwide in pharmaceutical, food and cosmetic industries due to the plethora of biological activities of its constituents. This study was done to evaluate the effects of dietary aloe vera on growth and lipid peroxidation in rainbow trout (Oncorhynchus mykiss). A total number of 480 O. mykiss (mean weight 9.50 ± 0.85 g) were randomized into four experimental groups including one control and three experimental groups that aloe vera was incorporated in their diet at 0.5, 1.0 and 2.0 g kg-1. Trial was done for eight weeks. Then biometry and blood sampling were done. Plasma malondialdehyde, ferric reducing ability of plasma and growth index were estimated at the end of study. The results showed that aloe vera extract did not affect growth indices. Malondialdehyde was increased in the experimental group compared to the control group but ferric reducing ability of plasma showed a decrease in experimental groups (p < 0.05) compared to the control group. Our findings showed that dietary aloe vera have adverse effects on antioxidant defense system in O. mykiss. PMID:25992253

  19. Gene expression in the liver of rainbow trout, Oncorhynchus mykiss, during the stress response

    USGS Publications Warehouse

    Momoda, T.S.; Schwindt, A.R.; Feist, G.W.; Gerwick, L.; Bayne, C.J.; Schreck, C.B.

    2007-01-01

    To better appreciate the mechanisms underlying the physiology of the stress response, an oligonucleotide microarray and real-time RT-PCR (QRT-PCR) were used to study gene expression in the livers of rainbow trout (Oncorhynchus mykiss). For increased confidence in the discovery of candidate genes responding to stress, we conducted two separate experiments using fish from different year classes. In both experiments, fish exposed to a 3??h stressor were compared to control (unstressed) fish. In the second experiment some additional fish were exposed to only 0.5??h of stress and others were sampled 21??h after experiencing a 3??h stressor. This 21??h post-stress treatment was a means to study gene expression during recovery from stress. The genes we report as differentially expressed are those that responded similarly in both experiments, suggesting that they are robust indicators of stress. Those genes are a major histocompatibility complex class 1 molecule (MHC1), JunB, glucose 6-phosphatase (G6Pase), and nuclear protein 1 (Nupr1). Interestingly, Nupr1 gene expression was still elevated 21??h after stress, which indicates that recovery was incomplete at that time. ?? 2007 Elsevier Inc. All rights reserved.

  20. Reduction in swimming performance in juvenile rainbow trout (Oncorhynchus mykiss) following sublethal exposure to pyrethroid insecticides.

    PubMed

    Goulding, Adam T; Shelley, Lesley K; Ross, Peter S; Kennedy, Christopher J

    2013-04-01

    While the lethal toxicity of pyrethroid insecticides to fish is well documented, their sublethal physio-behavioral effects remain poorly characterized. Known pyrethroid-associated changes to insect neuromuscular function may translate into similar effects in fish, thereby altering swimming ability and affecting foraging, predator avoidance, and migration. Three experiments were conducted using critical (Ucrit) and burst (Umax) swimming speeds to assess the sublethal effects of the pyrethroids permethrin and deltamethrin in juvenile rainbow trout (Oncorhynchus mykiss). Fish were exposed to deltamethrin (100, 200, or 300 ng/L) or permethrin (1, 2, or 3 μg/L) in water for 4 d, and assessed for swimming performance. Deltamethrin (200 and 300 ng/L) reduced Ucrit, but not Umax, while both swim performance measurements were unaffected by permethrin. Subsequent experiments used only Ucrit to assess deltamethrin exposure. In a time course experiment, deltamethrin (300 ng/L) reduced Ucrit after 1 and 4 d of exposure, but after 7 d of exposure Ucrit was fully recovered. Finally, deltamethrin (1, 2, or 3 μg/L) reduced Ucrit after 1h bath exposures similar to recommended protocols for deltamethrin based sea-lice treatment in aquaculture. The real-world implications of the revealed pyrethroid-associated swimming ability reductions in salmon may be important in areas close to aquaculture facilities. PMID:23318297

  1. Multiple biomarkers responses in juvenile rainbow trout, Oncorhynchus mykiss, after acute exposure to a fungicide propiconazole.

    PubMed

    Li, Zhi-Hua; Zlabek, Vladimir; Velisek, Josef; Grabic, Roman; Machova, Jana; Kolarova, Jitka; Li, Ping; Randak, Tomas

    2013-03-01

    In this study, the toxic effects of propiconazole (PCZ), a triazole fungicide present in aquatic environment, were studied in juvenile rainbow trout, Oncorhynchus mykiss, by acute toxicity test with the concentration of 5.04 mg/L (96 h LC50). Morphological indices, hematological parameters, liver xenobiotic-metabolizing response, and tissue antioxidant status were evaluated. Compared with the control group, fish exposed to PCZ showed significantly higher Leuko, PCV, MCHC, and hepatic EROD, and significantly lower MCV. CF and HSI were not significantly different among groups. SOD, CAT, GPx, and GR activities increased significantly in liver of experimental groups, but decreased significantly in gill. In general, antioxidant enzyme activity in intestine was less evident than in liver. Oxidative stress indices (levels of LPO and CP) were significantly higher in gill. Additionally, through chemometrics of all parameters measured in this study, two groups with 67.29% of total accumulated variance were distinguished. In short, the physiological and biochemical responses in different tissues of fish indicated that PCZ-induced the stressful environmental conditions. But according to PCZ residual status in the natural environment, more long-term experiments at lower concentrations will be necessary in the future. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2013. PMID:21384499

  2. Effect of a heavy metal model mixture on biological parameters of rainbow trout Oncorhynchus mykiss.

    PubMed

    Vosyliene, Milda Zita; Kazlauskiene, Nijole; Svecevicius, Gintaras

    2003-01-01

    The effects of a model mixture (HMMM) of seven heavy metals (Cu, Zn, Ni, Cr, Pb, Cd, Mn) on the rainbow trout Oncorhynchus mykiss at all stages of development (embryos, larvae, adults) were investigated based on the annual average concentrations of these metals in cooling waste waters discharging from Ignalina Nuclear Power Plant (Lithuania) into the Drŭksiai lake. According to mortality parameters, the most sensitive to HMMM were larvae, although no significant differences between the sensitivity of embryos and adult fish to HMMM were found. Maximal toxic effect of HMMM was observed during the hatching period. Long-term exposure to sublethal concentrations of HMMM affected embryo development, growth of larvae, their cardio-respiratory and behavioural responses, induced significant changes in morphological, morpho-physiological, physiological and haematological parameters of adult fish. Respiratory responses and growth parameters of fish were found to be the most sensitive to low concentrations of HMMM. Adult fish were capable of detecting and avoiding low, sublethal concentrations of HMMM. Heavy metals in a mixture at low concentrations were more toxic than single ones. According to the background of the damages induced by HMMM, after-effects in a fish organism, as well as in a whole population, can be predicted. PMID:12729042

  3. The immunoglobulin repertoire of the rainbow trout (Oncorhynchus mykiss): definition of nine Igh-V families.

    PubMed

    Roman, T; Charlemagne, J

    1994-01-01

    An Igh-V library was constructed from the head kidney cytoplasmic RNA of an 8.5-month-old non-immunized rainbow trout, Oncorhynchus mykiss, using the 5' RACE polymerase chain reaction. Six new Igh-V segments were identified, bringing to nine the number of Igh-V families actually defined in that species. A phylogenetic analysis shows that these nine Igh-V families can be classified into three major groups. The first includes the Igh-V1, Igh-V3, Igh-V4, and Igh-V7 families, and is homologous to the human and mouse Group III Igh-V families. The second includes the Igh-V5, Igh-V8, and Igh-V9 families and is more closely related to the Group I and Group II human and mouse Igh-V families. The third group includes the Igh-V2 and Igh-V6 families, which are not closely related to any other vertebrate Igh-V gene. Six Igh-J segments were characterized. They can recombine with Igh-V segments belonging to different families and there is a high level of junctional diversity between the Igh-V and Igh-J segments. PMID:8039829

  4. Nutrient content in the muscle and skin of fillets from farmed rainbow trout (Oncorhynchus mykiss).

    PubMed

    Rebolé, A; Velasco, S; Rodríguez, M L; Treviño, J; Alzueta, C; Tejedor, J L; Ortiz, L T

    2015-05-01

    The nutrient content in the muscle and edible skin parts of rainbow trout (Oncorhynchus mykiss) fillets, sampled at two growth stages, was evaluated. The average concentrations of protein and essential amino acids were higher in the muscle than in the skin. The chemical scores reached a value of 1.0 for the amino acids in the muscle and ranged from 0.40 (tryptophan) to 0.94 (threonine) in the skin. The average lipid content and the saturated fatty acids/polyunsaturated fatty acids and n-6/n-3 ratios were higher in the skin than in the muscle, whereas the proportion of docosahexaenoic acid (C22:6 n-3) was higher in the muscle. Significant differences were found for the essential minerals analysed, except for Cu. The concentrations of Na, K and Mg were higher and those of Ca, P, Fe, Mn and Zn were lower in the muscle than in the skin. Significant effects of the fish growth on the composition were detected. PMID:25529727

  5. Effects of atrazine on hepatic metabolism and endocrine homeostasis in rainbow trout (Oncorhynchus mykiss)

    SciTech Connect

    Salaberria, Iurgi Hansen, Bjorn Henrik; Asensio, Vega; Olsvik, Pal A.; Andersen, Rolf A.; Jenssen, Bjorn Munro

    2009-01-01

    The herbicide atrazine (ATZ) is one of the most widely used pesticides in the world and is now under scrutiny for its alleged capacity to disrupt the endocrine system. Exhibiting negligible interaction with the estrogen receptor (ER), ATZ's mode of action remains to be elucidated. ATZ may act as an inducer of the enzyme aromatase, which converts androgens to estrogens, although other mechanisms should also be taken into consideration such as impairment of hepatic metabolism. Therefore we administered juvenile rainbow trout (Oncorhynchus mykiss) a dose of either 2 or 200 {mu}g ATZ/kg, or of carrier control phosphate buffered saline (PBS) and we measured plasma concentrations of testosterone (T), 17beta-estradiol (E2) and vitellogenin (Vtg) 6 days after exposure. Simultaneously we analyzed hepatic gene expression of cytochrome P450 (CYP) 1A and pi-class glutathione S-transferase (GST-P), and catalase (CAT) activity. Although sex steroid levels showed no significant alterations, we found a dose-dependent increase in Vtg and a concomitant decrease in CYP1A. There was no effect of ATZ on GST-P mRNA levels but GST-P was positively correlated with CYP1A. Also, CYP1A was negatively correlated with liver CAT and E2, and varied with T concentrations in a hormetic manner. The results showed that ATZ can alter hepatic metabolism, induce estrogenic effects and oxidative stress in vivo, and that these effects are linked.

  6. Metabolism and elimination of benzocaine by rainbow-trout, Oncorhynchus mykiss

    USGS Publications Warehouse

    Meinertz, J.R.; Gingerich, W.H.; Allen, J.L.

    1991-01-01

    1. Branchial and urinary elimination of benzocaine residues was evaluated in adult rainbow trout, oncorhynchus mykiss, given a single dorsal aortic dose of c-14-benzocaine hydrochloride.^2. Branchial elimination of benzocaine residues was rapid and accounted for 59.2% Of the dose during the first 3 h after dosing. Renal elimination of radioactivity was considerably slower; the kidney excreted 2.7% Dose within 3 h and 9.0% Within 24 h. Gallbladder bile contained 2.0% Dose 24 h after injection.^3. Of the radioactivity in radiochromatograms from water taken 3 min after injection, 87.3% Was benzocaine and 12.7% Was n-acetylated benzocaine. After 60 min, 32.7% Was benzocaine and 67.3% Was n-acetylated benzocaine.^4. Of the radioactivity in radiochromatograms from urine taken 1 h after dosing, 7.6% Was para-aminobenzoic acid, 59.7% Was n-acetylated para-aminobenzoic acid, 19.5% Was benzocaine, and 8.0% Was n-acetylated benzocaine. The proportion of the radioactivity in urine changed with time so that by 20 h, 1.0% Was para-aminobenzoic acid and 96.6% Was n-acetylated para-aminobenzoic acid.^5. Benzocaine and a more hydrophobic metabolite, n-acetylated benzocaine, were eliminated primarily through the gills; renal and biliary pathways were less significant elimination routes for benzocaine residues.

  7. The effect of creosote on vitellogenin production in rainbow trout (Oncorhynchus mykiss)

    USGS Publications Warehouse

    Sherry, J.P.; Whyte, J.J.; Karrow, N.A.; Gamble, A.; Boerman, H.J.; Bol, N.C.; Dixon, D.G.; Solomon, K.R.

    2006-01-01

    As part of a broader investigation into the effects of creosote treatments on the aquatic biota in pond microcosms, we examined the possible implications for vitellogenin (Vtg) production in Oncorhynchus mykiss [rainbow trout (RT)]. Vtg is the precursor of egg yolk protein and has emerged as a useful biomarker of exposure to estrogenic substances. Our a priori intent was to assess the ability of the creosote treatments (nominal cresoste concentrations were 0, 3, and 10 ??l/L immediately after the last subsurface addition) to induce estrogenic responses in RT. The data showed no evidence of an estrogenic response in the treated fish. During the course of the experiment, however, the fish matured and began to produce Vtg, probably in response to endogenous estrogen. A posteriori analysis of the Vtg data from the maturing fish showed that after 28 days, the plasma Vtg concentrations were about 15-fold lower in fish from the creosote-treated microcosms compared with fish from the reference microcosm. Although the experiment design does not permit mechanistic insights, our observation suggests that exposure of female fish to PAH mixtures such as creosote can impair the production of Vtg with possible health implications for embryos and larvae. ?? 2006 Springer Science+Business Media, Inc.

  8. Reduced growth of rainbow trout (Oncorhynchus mykiss) fed a live invertebrate diet pre-exposed to metal-contaminated sediments.

    PubMed

    Hansen, James A; Lipton, Joshua; Welsh, Paul G; Cacela, David; MacConnell, Beth

    2004-08-01

    Juvenile rainbow trout (Oncorhynchus mykiss) were fed live diets of Lumbriculus variegatus cultured in metal-contaminated sediments from the Clark Fork River Basin (MT, USA), an uncontaminated reference sediment, or an uncontaminated culture medium. Fish were tested in individual chambers; individual growth as well as the nutritional quality and caloric value of each trout's consumed diet were determined. Growth was measured following 14, 28, 42, 56, and 67 d of exposure. A subset of fish was sampled at 35 d for whole-body metals. Metals (whole body, digestive tract, and liver) and histology were measured at the end of the test. We observed significant growth inhibition in trout fed the contaminated diets; growth inhibition was associated with reductions in conversion of food energy to biomass rather than with reduced food intake. Growth inhibition was negatively correlated with As in trout tissue residues. Histological changes in contaminated treatments included hepatic necrosis and degenerative alterations in gallbladder. The present study provides evidence that metal-contaminated sediments can pose a hazard to trout health through a dietary exposure pathway. PMID:15352479

  9. Comparative analysis of innate immune responses to Streptococcus phocae strains in Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss).

    PubMed

    Salazar, Soraya; Oliver, Cristian; Yáñez, Alejandro J; Avendaño-Herrera, Ruben

    2016-04-01

    Streptococcus phocae subsp. salmonis is a Gram-positive bacterium that causes mortality only in Atlantic salmon (Salmo salar) farmed in Chile, even when this species is co-cultured with rainbow trout (Oncorhynchus mykiss). This susceptibility could be determined by innate immune response components and their responses to bacterial infection. This fish pathogen shares subspecies status with Streptococcus phocae subsp. phocae isolated from seals. The present study compared innate immune system mechanisms in Atlantic salmon and rainbow trout when challenged with different S. phocae, including two isolates from Atlantic salmon (LM-08-Sp and LM-13-Sp) and two from seal (ATCC 51973(T) and P23). Streptococcus phocae growth was evaluated in the mucus and serum of both species, with rainbow trout samples evidencing inhibitory effects. Lysozyme activity supported this observation, with significantly higher (p < 0.01) expression in rainbow trout serum and mucus as compared to Atlantic salmon. No differences were found in phagocytic capacity between fish species when stimulated with ATCC 51973(T) and P23. Against all S. phocae strains, rainbow trout and Atlantic salmon showed up to two-fold increased bactericidal activity, and rainbow trout demonstrated up to three-fold greater reactive oxygen species production in macrophages. In conclusion, the non-specific humoral and cellular barriers of Atlantic salmon were immunologically insufficient against S. phocae subsp. salmonis, thereby facilitating streptococcosis. Moreover, the more robust response of rainbow trout to S. phocae could not be attributed to any specific component of the innate immune system, but was rather the consequence of a combined response by the evaluated components. PMID:26876354

  10. Analysis of trade-offs between threats of invasion by nonnative brook trout (Salvelinus fontinalis) and intentional isolation for native westslope cutthroat trout (Oncorhynchus clarkii lewisi)

    USGS Publications Warehouse

    Peterson, D.P.; Rieman, B.E.; Dunham, J.B.; Fausch, K.D.; Young, M.K.

    2008-01-01

    Native salmonid fishes often face simultaneous threats from habitat fragmentation and invasion by nonnative trout species. Unfortunately, management actions to address one may create or exacerbate the other. A consistent decision process would include a systematic analysis of when and where intentional use or removal of barriers is the most appropriate action. We developed a Bayesian belief network as a tool for such analyses. We focused on native westslope cutthroat trout (Oncorhynchus clarkii lewisi) and nonnative brook trout (Salvelinus fontinalis) and considered the environmental factors influencing both species, their potential interactions, and the effects of isolation on the persistence of local cutthroat trout populations. The trade-offs between isolation and invasion were strongly influenced by size and habitat quality of the stream network to be isolated and existing demographic linkages within and among populations. An application of the model in several sites in western Montana (USA) showed the process could help clarify management objectives and options and prioritize conservation actions among streams. The approach can also facilitate communication among parties concerned with native salmonids, nonnative fish invasions, barriers and intentional isolation, and management of the associated habitats and populations. ?? 2008 NRC.

  11. Assessing the impacts of river regulation on native bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarkii lewisi) habitats in the upper Flathead River, Montana, USA

    USGS Publications Warehouse

    Muhlfeld, Clint C.; Jones, Leslie A.; Kotter, D.; Miller, William J.; Geise, Doran; Tohtz, Joel; Marotz, Brian

    2012-01-01

    Hungry Horse Dam on the South Fork Flathead River, Montana, USA, has modified the natural flow regimen for power generation, flood risk management and flow augmentation for anadromous fish recovery in the Columbia River. Concern over the detrimental effects of dam operations on native resident fishes prompted research to quantify the impacts of alternative flow management strategies on threatened bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarkii lewisi) habitats. Seasonal and life‐stage specific habitat suitability criteria were combined with a two‐dimensional hydrodynamic habitat model to assess discharge effects on usable habitats. Telemetry data used to construct seasonal habitat suitability curves revealed that subadult (fish that emigrated from natal streams to the river system) bull trout move to shallow, low‐velocity shoreline areas at night, which are most sensitive to flow fluctuations. Habitat time series analyses comparing the natural flow regimen (predam, 1929–1952) with five postdam flow management strategies (1953–2008) show that the natural flow conditions optimize the critical bull trout habitats and that the current strategy best resembles the natural flow conditions of all postdam periods. Late summer flow augmentation for anadromous fish recovery, however, produces higher discharges than predam conditions, which reduces the availability of usable habitat during this critical growing season. Our results suggest that past flow management policies that created sporadic streamflow fluctuations were likely detrimental to resident salmonids and that natural flow management strategies will likely improve the chances of protecting key ecosystem processes and help to maintain and restore threatened bull trout and westslope cutthroat trout populations in the upper Columbia River Basin.

  12. Emigration of Natural and Hatchery Naco x (Chinook salmon; Oncorhynchus tshawytscha) and Heeyey (Steelhead; Oncorhynchus mykiss) Smolts from the Imnaha River, Oregon from 5 October 2006 to 21 June 2007, Annual Report 2007.

    SciTech Connect

    Michaels, Brian; Espinosa, Neal

    2009-02-18

    This report summarizes the Nez Perce Tribe (NPT) Department of Fisheries Resources Management (DFRM) results for the Lower Snake River Compensation Plan (LSRCP) Hatchery Evaluation studies and the Imnaha River Smolt Monitoring Program (SMP) for the 2007 smolt migration from the Imnaha River, Oregon. These studies are closely coordinated and provide information about juvenile natural and hatchery spring/summer Naco x (Chinook Salmon; Oncorhynchus tshawytscha) and Heeyey (steelhead; O. mykiss) biological characteristics, emigrant timing, survival, arrival timing and travel time to the Snake River dams and McNary Dam (MCD) on the Columbia River. These studies provide information on listed Naco x (Chinook salmon) and Heeyey (steelhead) for the Federal Columbia River Power System (FCRPS) Biological Opinion (NMFS 2000). The Lower Snake River Compensation Plan program's goal is to maintain a hatchery production program of 490,000 Naco x (Chinook salmon) and 330,000 Heeyey (steelhead) for annual release in the Imnaha River (Carmichael et al. 1998, Whitesel et al. 1998). These hatchery releases occur to compensate for fish losses due to the construction and operation of the four lower Snake River hydroelectric facilities. One of the aspects of the LSRCP hatchery evaluation studies in the Imnaha River is to determine natural and hatchery Naco x (Chinook salmon) and Heeyey (steelhead) smolt performance, emigration characteristics and survival (Kucera and Blenden 1998). A long term monitoring effort was established to document smolt emigrant timing and post release survival within the Imnaha River, estimate smolt survival downstream to McNary Dam, compare natural and hatchery smolt performance, and collect smolt-to-adult return information. This project collects information for, and is part of, a larger effort entitled Smolt Monitoring by Federal and Non-Federal Agencies (BPA Project No. 198712700). This larger project provides data on movement of smolts out of major drainages

  13. Phylogenetic relationships of Iranian infectious hematopoietic necrosis virus of rainbow trout (Oncorhynchus mykiss) based on the glycoprotein gene.

    PubMed

    Adel, Milad; Amiri, Alireza Babaalian; Dadar, Maryam; Breyta, Rachel; Kurath, Gael; Laktarashi, Bahram; Ghajari, Amrolah

    2016-03-01

    Infectious hematopoietic necrosis virus (IHNV), a member of family Rhabdoviridae and genus Novirhabdoviridae, causes a highly lethal disease of salmon and trout. In Iran IHNV was first detected in 2001 on farms rearing rainbow trout (Oncorhynchus mykiss). To evaluate the genetic relationships of IHNV from northern and western Iran, the sequences of a 651-nt region of the glycoprotein gene were determined for two Iranian isolates. These sequences were analyzed to evaluate their genetic relatedness to worldwide isolates representing the five known genogroups of IHNV. Iranian isolates were most closely related to European isolates within the genogroup E rather than those of North American genogroups U, M and L, or the Asian genogroup J. It appears that Iranian IHNV was most likely introduced to Iran from a source in Europe by the movement of contaminated fish eggs. PMID:26602428

  14. Phylogenetic relationships of Iranian infectious hematopoietic necrosis virus of rainbow trout (Oncorhynchus mykiss) based on the glycoprotein gene

    USGS Publications Warehouse

    Adel, Milad; Amiri, Alireza Babaalian; Dada, Maryam; Kurath, Gael; Laktarashi, Bahram; Ghajari, Amrolah; Breyta, Rachel

    2016-01-01

    Infectious hematopoietic necrosis virus (IHNV), a member of family Rhabdoviridae and genus Novirhabdoviridae, causes a highly lethal disease of salmon and trout. In Iran IHNV was first detected in 2001 on farms rearing rainbow trout (Oncorhynchus mykiss). To evaluate the genetic relationships of IHNV from northern and western Iran, the sequences of a 651-nt region of the glycoprotein gene were determined for two Iranian isolates. These sequences were analyzed to evaluate their genetic relatedness to worldwide isolates representing the five known genogroups of IHNV. Iranian isolates were most closely related to European isolates within the genogroup E rather than those of North American genogroups U, M and L, or the Asian genogroup J. It appears that Iranian IHNV was most likely introduced to Iran from a source in Europe by the movement of contaminated fish eggs.

  15. A new measurement approach of ionizing radiation in irradiated trout (Oncorhynchus mykiss) by Randomly Polymorphic DNA-Polymerase Chain Reaction.

    PubMed

    Şakalar, Ergün; Mol, Sühendan

    2016-05-01

    Trout (Oncorhynchus mykiss) were irradiated at doses of 0.250, 0.500, 1, 3, 5, 7 and 9 kGy in gamma cell. DNAs were extracted from the irradiated samples before and after storage. 1ERP primers were designed, and RAPD-PCR (Randomly Polymorphic DNA-Polymerase Chain Reaction) was applied to make randomly amplifications on the DNA of the irradiated samples. Agarose gel profiles of irradiated fish were obtained to determine change of band profiles. In addition, DNA fragmentation occurring in each dose was determined by comet assay for the verification of methodology developed in this study. The molecular methodology was developed to estimate ionizing radiation (IR) level in irradiated fish. This methodology allows the analysis of the trout irradiated up to the dose limit of around 0.5 kGy and stored for a period of three months. PMID:27407216

  16. Electron microscope studies of the in vitro phagocytosis of Mycobacterium spp. by rainbow trout Oncorhynchus mykiss head kidney macrophages.

    PubMed

    Chen, S C; Adams, A; Thompson, K D; Richards, R H

    1998-03-01

    The cytological response of rainbow trout Oncorhynchus mykiss head kidney macrophages to ingested Mycobacterium spp. was examined in vitro. Mycobacterium marinum or Mycobacterium sp. TB267 isolated from snakehead fish Channa striata Bloch were opsonised with either fresh rainbow trout serum, serum which had been heat-inactivated, or rainbow trout antiserum against the extracellular products (ECP) of the 2 Mycobacterium spp. A monoclonal antibody against the ECP was also used as an opsonin. Suspensions of macrophages were prepared (1 ml of 1 x 10(7) cells ml-1), mixed with the opsonised bacteria (100 microliters of 2 x 10(9) ml-1), and incubated at 18 degrees C for 0.5, 1, 2, 4 or 6 h to allow phagocytosis to occur. A quantitative evaluation of the phagocytosis of the mycobacteria by the macrophages was carried out by electron microscopy. Macrophage phagosomes and their contents were examined and numbers of intact and partially degraded bacteria determined. Pre-labelling dense granules (secondary lysosomes) with ferritin enabled phagosome lysosome fusion to be identified and their frequency determined. Opsonisation of the mycobacteria was found to greatly enhance the phagocytic and killing activity of the rainbow trout macrophages. PMID:9676251

  17. Differential virulence mechanisms of infectious hematopoietic necrosis virus in rainbow trout (Oncorhynchus mykiss) include host entry and virus replication kinetics

    USGS Publications Warehouse

    Penaranda, M.M.D.; Purcell, M.K.; Kurath, G.

    2009-01-01

    Host specificity is a phenomenon exhibited by all viruses. For the fish rhabdovirus infectious hematopoietic necrosis virus (IHNV), differential specificity of virus strains from the U and M genogroups has been established both in the field and in experimental challenges. In rainbow trout (Oncorhynchus mykiss), M IHNV strains are consistently more prevalent and more virulent than U IHNV. The basis of the differential ability of these two IHNV genogroups to cause disease in rainbow trout was investigated in live infection challenges with representative U and M IHNV strains. When IHNV was delivered by intraperitoneal injection, the mortality caused by U IHNV increased, indicating that the low virulence of U IHNV is partly due to inefficiency in entering the trout host. Analyses of in vivo replication showed that U IHNV consistently had lower prevalence and lower viral load than M IHNV during the course of infection. In analyses of the host immune response, M IHNV-infected fish consistently had higher and longer expression of innate immune-related genes such as Mx-1. This suggests that the higher virulence of M IHNV is not due to suppression of the immune response in rainbow trout. Taken together, the results support a kinetics hypothesis wherein faster replication enables M IHNV to rapidly achieve a threshold level of virus necessary to override the strong host innate immune response. ?? 2009 SGM.

  18. Biological control of Aeromonas salmonicida subsp. salmonicida infection in rainbow trout (Oncorhynchus mykiss) using Aeromonas phage PAS-1.

    PubMed

    Kim, J H; Choresca, C H; Shin, S P; Han, J E; Jun, J W; Park, S C

    2015-02-01

    The potential control efficacy of Aeromonas phage PAS-1 was evaluated against Aeromonas salmonicida subsp. salmonicida infection in rainbow trout (Oncorhynchus mykiss) model in this study. The phage was co-cultured with the virulent A. salmonicida subsp. salmonicida strain AS05 that possesses the type III secretion system (TTSS) ascV gene, and efficient bacteriolytic activity was observed against the bacteria. The administration of PAS-1 in rainbow trout demonstrated that the phage was cleared from the fish within 200 h post-administration, and a temporal neutralizing activity against the phage was detected in the sera of phage-administrated fish. The administration of PAS-1 (multiplicity of infection: 10 000) in A. salmonicida subsp. salmonicida infected rainbow trout model showed notable protective effects, with increased survival rates and mean times to death. These results demonstrated that Aeromonas phage PAS-1 could be considered as an alternative biological control agent against A. salmonicida subsp. salmonicida infections in rainbow trout culture. PMID:23594036

  19. Isolation and identification of viral hemorrhagic septicemia virus (VHSV) from farmed rainbow trout (Oncorhynchus mykiss) in Iran.

    PubMed

    Ahmadivand, Sohrab; Soltani, Mehdi; Mardani, Karim; Shokrpoor, Sara; Rahmati-Holasoo, Hooman; Mokhtari, Abbas; Hasanzadeh, Reza

    2016-04-01

    Viral hemorrhagic septicemia virus (VHSV) is a rhabdovirus that causes one of the most important fish diseases in rainbow trout (Oncorhynchus mykiss) production industry. During the present study from October 2014 to July 2015, the virus causing viral hemorrhagic septicemia (VHS) was isolated and identified in rainbow trout farms from five of sixteen farms experiencing mass mortalities in six provinces of Iran with major trout production. Cumulative mortalities at VHSV-positive farms ranged from 30 to 70%. Clinical signs of disease included exophthalmia, petechial hemorrhages in the mandible and around the eyes, a swollen abdomen and darkening of the integument, widespread petechiae of the musculature and pyloric regions, severe congestion of the kidney, and pale enlarged livers. In addition, histopathologic examinations of tissues showed severe lesions in muscle, kidney and liver, which were compatible with those already described for VHS. Furthermore, homogenates tissues of diseased fish induced cytopathic effects (CPE) in CHSE-214 cells, and confirmatory diagnosis of VHS was made by RT-PCR reactions. To our knowledge, this is the first report of isolation and identification of VHSV from farmed trout in Iran, which may have originated from Europe. PMID:26777311

  20. Boule gene expression underpins the meiotic arrest in spermatogenesis in male rainbow trout (Oncorhynchus mykiss) exposed to DEHP and butachlor.

    PubMed

    Ahmadivand, Sohrab; Farahmand, Hamid; Teimoori-Toolabi, Ladan; Mirvaghefi, Alireza; Eagderi, Soheil; Geerinckx, Tom; Shokrpoor, Sara; Rahmati-Holasoo, Hooman

    2016-01-01

    Boule, the ancestor of the DAZ (Deleted in AZoospermia) gene family, in most organisms is mainly involved in male meiosis. The present study investigates the effects of the plasticizer DEHP (50mg/kg body weight) and herbicide butachlor (0.39mg/L) on male rainbow trout (Oncorhynchus mykiss) for a 10-day period in two independent experiments. The results showed that plasma testosterone (T) concentrations were significantly lower in fish exposed to either DEHP or butachlor compared to the control fish (P<0.05). Fish showed a significantly elevated hepatosomatic index (HSI) in the butachlor treatment (P<0.05). However, no significant difference was observed in HSI values in the DEHP treatment (P>0.05). In addition, no significant differences were found in the gonadosomatic index (GSI) in both DEHP and butachlor treatments (P>0.05). Histologically, testes of male trout in the control groups were well differentiated and filled with large numbers of cystic structures containing spermatozoa. In contrast, the testes of male trout contained mostly spermatocytes with few spermatozoa in both treated group, suggesting that DEHP and butachlor may inhibit the progression of meiosis. Also, boule gene expression was significantly lower in the testes of male trout affected by DEHP and butachlor in comparison with their control groups (P<0.05), which confirmed the meiotic arrest in affected trout. Based on the results, the present study demonstrated that DEHP and butachlor can inhibit the progression of spermatogenesis in male trout, potentially by causing an arrest of meiosis, maybe due to down-regulation of boule gene expression through T and/or IGF1 via ERK1/2 signaling in T-independent pathways. In addition, these results confirmed that boule can be considered as a predictive marker to assess meiotic efficiency. PMID:26027538

  1. The effect of bifenthrin on the dopaminergic pathway in juvenile rainbow trout (Oncorhynchus mykiss).

    PubMed

    Crago, Jordan; Schlenk, Daniel

    2015-05-01

    Bifenthrin is a type I pyrethroid pesticide, which has been shown to increase plasma estrogen concentrations in several fish models. The mechanism of action by which bifenthrin alters 17β-estradiol (E2) is unclear. E2 biosynthesis is regulated through pituitary follicle stimulating hormone, which is directly controlled by hypothalamic gonadotropin releasing hormone (GnRH2). Since dopaminergic signaling significantly influences GnRH2 release in fish, the goal of the study was to determine the effect of a 96 h and 2 weeks exposure to bifenthrin on dopaminergic signaling in juvenile rainbow trout (Oncorhynchus mykiss) (RT). Our results indicated that a decrease in dopamine receptor 2A (DR2A) expression was associated with a trend toward an increase in plasma E2 following exposure at 96 h and 2 weeks, and a significant increase in the relative expression of vitellogenin mRNA at 2 weeks. DR2A mRNA expression decreased 426-fold at 96 h and 269-fold at 2 weeks in the brains of 1.5 ppb (3.55 pM) bifenthrin treated RT. There was an increase in tyrosine hydroxylase transcript levels at 96 h, which is indicative of dopamine production in the brains of the 1.5 ppb (3.55 pM) bifenthrin treated RT. A significant increase in the relative expression of GnRH2 was observed at 96 h but a significant decrease was noted after 2 weeks exposure indicating potential feedback loop activation. These results indicate that the estrogenic-effects of bifenthrin may result in part from changes in signaling within the dopaminergic pathway, but that other feedback pathways may also be involved. PMID:25781393

  2. The effect of peptidoglycan enriched diets on antimicrobial peptide gene expression in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Casadei, Elisa; Bird, Steve; Vecino, Jose L González; Wadsworth, Simon; Secombes, Christopher J

    2013-02-01

    The aim of this study was to investigate the effect of feeding rainbow trout (Oncorhynchus mykiss) peptidoglycan (PG) enriched diets on antimicrobial peptide (AMP) gene expression. Fish were divided into 5 groups and fed diets containing 0, 5, 10, 50 and 100 mg PG/Kg, and sampled 1, 7 and 14 days later. The expression of eight AMP genes (four defensins, two cathelicidins and two liver expressed AMPs) was determined in skin, gill, gut and liver, tissues important for first lines of defence or production of acute phase proteins. Up-regulation of many AMPs was found after feeding the PG enriched diets, with sequential expression seen over the time course studied, where defensins were typically expressed early and cathelicidins and LEAPs later on. A number of clear differences in AMP responsiveness between the tissues examined were also apparent. Of the four PG concentrations used, 5 mg PG/Kg did not always elicit AMP gene induction or to the same degree as seen with the other diets. The three higher dose groups generally showed similar trends although differences in fold change were more pronounced in the 50 and 100 mg PG/Kg groups. Curiously several AMPs were down-regulated after 14 days of feeding in gills, gut and liver. Nevertheless, overall the PG enriched diets had a positive effect on AMP expression. Further investigations now need to be undertaken to confirm whether this higher AMP gene expression correlates with protection against common bacterial diseases and if PG enriched diets have value as a means to temporarily boost the piscine immune system. PMID:23220715

  3. Effects of intracerebroventricular administered fluoxetine on cardio-ventilatory functions in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Kermorgant, Marc; Lancien, Frédéric; Mimassi, Nagi; Tyler, Charles R; Le Mével, Jean-Claude

    2014-09-01

    Fluoxetine (FLX) is a selective serotonin (5-HT) reuptake inhibitor present in the aquatic environment which is known to bioconcentrate in the brains of exposed fish. FLX acts as a disruptor of various neuroendocrine functions in the brain, but nothing is known about the possible consequence of FLX exposure on the cardio-ventilatory system in fish. Here we undertook to investigate the central actions of FLX on ventilatory and cardiovascular function in unanesthetized rainbow trout (Oncorhynchus mykiss). Intracerebroventricular (ICV) injection of FLX (dosed between 5 and 25 μg) resulted in a significantly elevated total ventilation (VTOT), with a maximum hyperventilation of +176% (at a dose of 25μg) compared with vehicle injected controls. This increase was due to an increase in ventilatory amplitude (VAMP: +126%) with minor effects on ventilatory frequency. The highest dose of FLX (25 μg) produced a significant increase in mean dorsal aortic blood pressure (PDA: +20%) without effects on heart rate (ƒH). In comparison, intra-arterial injections of FLX (500-2,500 μg) had no effect on ventilation but the highest doses increased both PDA and ƒH. The ICV and IA cardio-ventilatory effects of FLX were very similar to those previously observed following injections of 5-HT, indicating that FLX probably acts via stimulating endogenous 5-HT activity through inhibition of 5-HT transporter(s). Our results demonstrate for the first time in fish that FLX administered within the brain exerts potent stimulatory effects on ventilation and blood pressure increase. The doses of FLX given to fish in our study are higher than the brain concentrations of FLX in fish that result from acute exposure to FLX through the water. Nonetheless, our results indicate possible disrupting action of long term exposure to FLX discharged into the environment on central target sites sensitive to 5-HT involved in cardio-ventilatory control. PMID:24681193

  4. The interactive toxicity of cadmium, copper, and zinc to Ceriodaphnia dubia and rainbow trout (Oncorhynchus mykiss).

    PubMed

    Naddy, Rami B; Cohen, Adam S; Stubblefield, William A

    2015-04-01

    Traditionally, aquatic toxicity studies examine the toxicity of a single chemical to an organism. Organisms in nature, however, may be exposed to multiple toxicants. Given this is a more realistic exposure scenario in situ, the authors sought to understand the interactive toxicity of multiple metals to aquatic organisms. The authors performed a series of studies using equitoxic mixtures of cadmium, copper, and zinc to 2 aquatic organisms, rainbow trout (Oncorhynchus mykiss) and the waterflea, Ceriodaphnia dubia. Single metal toxicity tests were conducted to determine the acute median lethal concentration (LC50) values for O. mykiss and short-term, chronic median effective concentration (EC50) values for C. dubia. All 3 metals were then combined in equitoxic concentrations for subsequent mixture studies using a toxic unit (TU) approach (i.e., 1 TU = EC50 or LC50). For C. dubia, the mixture study showed greater-than-additive effects in hard water (TU-based EC50 = 0.74 TU), but less-than-additive effects in soft water (TU-based EC50 = 1.93 TU). The mixture effects for O. mykiss showed less-than-additive effects in both hard and soft waters, with TU-based LC50 values of 2.33 total TU and 2.22 total TU, respectively. These data are useful in helping understand metal mixture toxicity in aquatic systems and indicate that although in most situations the assumption of additivity of metal mixture toxicity is valid, under certain conditions it may not be sufficiently protective. PMID:25641563

  5. Distribution of T Cells in Rainbow Trout (Oncorhynchus mykiss) Skin and Responsiveness to Viral Infection

    PubMed Central

    Leal, Esther; Granja, Aitor G.; Zarza, Carlos; Tafalla, Carolina

    2016-01-01

    Although the skin constitutes the first line of defense against waterborne pathogens, there is a great lack of information regarding the skin associated lymphoid tissue (SALT) and whether immune components of the skin are homogeneously distributed through the surface of the fish is still unknown. In the current work, we have analyzed the transcription of several immune genes throughout different rainbow trout (Oncorhynchus mykiss) skin areas. We found that immunoglobulin and chemokine gene transcription levels were higher in a skin area close to the gills. Furthermore, this skin area as well as other anterior sections also transcribed significantly higher levels of many different immune genes related to T cell immunity such as T cell receptor α (TCRα), TCRγ, CD3, CD4, CD8, perforin, GATA3, Tbet, FoxP3, interferon γ (IFNγ), CD40L and Eomes in comparison to posterior skin sections. In agreement with these results, immunohistochemical analysis revealed that anterior skin areas had a higher concentration of CD3+ T cells and flow cytometry analysis confirmed that the percentage of CD8+ T lymphocytes was also higher in anterior skin sections. These results demonstrate for the first time that T cells are not homogeneously distributed throughout the teleost skin. Additionally, we studied the transcriptional regulation of these and additional T cell markers in response to a bath infection with viral hemorrhagic septicemia virus (VHSV). We found that VHSV regulated the transcription of several of these T cell markers in both the skin and the spleen; with some differences between anterior and posterior skin sections. Altogether, our results point to skin T cells as major players of teleost skin immunity in response to waterborne viral infections. PMID:26808410

  6. Linking Personality to Larval Energy Reserves in Rainbow Trout (Oncorhynchus mykiss)

    PubMed Central

    Andersson, Madelene Åberg; Höglund, Erik

    2012-01-01

    There is a surging interest in the evolution, ecology and physiology of personality differences. However, most of the studies in this research area have been performed in adult animals. Trait variations expressed early in development and how they are related to the ontogeny of an animal’s personality are far less studied. Genetic differences as well as environmental factors causing functional variability of the central serotonergic system have been related to personality differences in vertebrates, including humans. Such gene-environment interplay suggests that the central serotonergic system plays an important role in the ontogeny of personality traits. In salmonid fishes, the timing of emergence from spawning nests is related to energy reserves, aggression, and social dominance. However, it is currently unknown how the size of the yolk reserve is reflected on aggression and dominance, or if these traits are linked to differences in serotonergic transmission in newly emerged larvae. In this study we investigated the relationship between yolk reserves, social dominance, and serotonergic transmission in newly emerged rainbow trout (Oncorhynchus mykiss) larvae. This was conducted by allowing larvae with the same emergence time, but with different yolk sizes, to interact in pairs for 24 h. The results show that individuals with larger yolks performed more aggressive acts, resulting in a suppression of aggression in individuals with smaller yolks. A higher brain serotonergic activity confirmed subordination in larvae with small yolks. The relationship between social dominance and yolk size was present in siblings, demonstrating a link between interfamily variation in energy reserves and aggression, and suggests that larger yolk reserves fuel a more aggressive personality during the initial territorial establishment in salmonid fishes. Furthermore, socially naïve larvae with big yolks had lower serotonin levels, suggesting that other factors than the social

  7. Distribution of T Cells in Rainbow Trout (Oncorhynchus mykiss) Skin and Responsiveness to Viral Infection.

    PubMed

    Leal, Esther; Granja, Aitor G; Zarza, Carlos; Tafalla, Carolina

    2016-01-01

    Although the skin constitutes the first line of defense against waterborne pathogens, there is a great lack of information regarding the skin associated lymphoid tissue (SALT) and whether immune components of the skin are homogeneously distributed through the surface of the fish is still unknown. In the current work, we have analyzed the transcription of several immune genes throughout different rainbow trout (Oncorhynchus mykiss) skin areas. We found that immunoglobulin and chemokine gene transcription levels were higher in a skin area close to the gills. Furthermore, this skin area as well as other anterior sections also transcribed significantly higher levels of many different immune genes related to T cell immunity such as T cell receptor α (TCRα), TCRγ, CD3, CD4, CD8, perforin, GATA3, Tbet, FoxP3, interferon γ (IFNγ), CD40L and Eomes in comparison to posterior skin sections. In agreement with these results, immunohistochemical analysis revealed that anterior skin areas had a higher concentration of CD3(+) T cells and flow cytometry analysis confirmed that the percentage of CD8(+) T lymphocytes was also higher in anterior skin sections. These results demonstrate for the first time that T cells are not homogeneously distributed throughout the teleost skin. Additionally, we studied the transcriptional regulation of these and additional T cell markers in response to a bath infection with viral hemorrhagic septicemia virus (VHSV). We found that VHSV regulated the transcription of several of these T cell markers in both the skin and the spleen; with some differences between anterior and posterior skin sections. Altogether, our results point to skin T cells as major players of teleost skin immunity in response to waterborne viral infections. PMID:26808410

  8. Effect of starvation on global gene expression and proteolysis in rainbow trout (Oncorhynchus mykiss)

    PubMed Central

    Salem, Mohamed; Silverstein, Jeff; Rexroad, Caird E; Yao, Jianbo

    2007-01-01

    Background Fast, efficiently growing animals have increased protein synthesis and/or reduced protein degradation relative to slow, inefficiently growing animals. Consequently, minimizing the energetic cost of protein turnover is a strategic goal for enhancing animal growth. Characterization of gene expression profiles associated with protein turnover would allow us to identify genes that could potentially be used as molecular biomarkers to select for germplasm with improved protein accretion. Results We evaluated changes in hepatic global gene expression in response to 3-week starvation in rainbow trout (Oncorhynchus mykiss). Microarray analysis revealed a coordinated, down-regulated expression of protein biosynthesis genes in starved fish. In addition, the expression of genes involved in lipid metabolism/transport, aerobic respiration, blood functions and immune response were decreased in response to starvation. However, the microarray approach did not show a significant increase of gene expression in protein catabolic pathways. Further studies, using real-time PCR and enzyme activity assays, were performed to investigate the expression of genes involved in the major proteolytic pathways including calpains, the multi-catalytic proteasome and cathepsins. Starvation reduced mRNA expression of the calpain inhibitor, calpastatin long isoform (CAST-L), with a subsequent increase in the calpain catalytic activity. In addition, starvation caused a slight but significant increase in 20S proteasome activity without affecting mRNA levels of the proteasome genes. Neither the mRNA levels nor the activities of cathepsin D and L were affected by starvation. Conclusion These results suggest a significant role of calpain and 20S proteasome pathways in protein mobilization as a source of energy during fasting and a potential association of the CAST-L gene with fish protein accretion. PMID:17880706

  9. Evaluation of the Reproductive Success of Wild and Hatchery Steelhead in Hatchery and Natural and Hatchery Environments : Annual Report for 2008.

    SciTech Connect

    Quinn, Thomas P.; Seamons, todd; Hauser, Lorenz; Naish, Kerry

    2008-12-05

    This report summarizes the field, laboratory, and analytical work from December 2007 through November 2008 on a research project that investigates interactions and comparative reproductive success of wild and hatchery origin steelhead (Oncorhynchus mykiss) trout in Forks Creek, a tributary of the Willapa River in southwest Washington. First, we continued to successfully sample hatchery and wild (i.e., naturally spawned) adult and wild smolt steelhead at Forks Creek. Second, we revealed microsatellite genotype data for adults and smolts through brood year 2008. Finally, four formal scientific manuscripts were published in 2008 and two are in press, one is in revision and two are in preparations.

  10. Comparing the effects of high vs. low nitrate on the health, performance, and welfare of juvenile rainbow trout Oncorhynchus mykiss within water recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research indicates that rainbow trout (Oncorhynchus mykiss) begin to exhibit health and welfare problems when cultured within water recirculating aquaculture systems (WRAS) operated at low exchange (6.7 days hydraulic retention time) and a mean feed loading rate of 4.1 kg feed/m3 daily make...